chapter 01 - 導言

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By: Anthony Bedford and Wallace Fowler

Engineering

Mechanics:

STATICS

Fifth Edition

in SI Units

Chapter 1:Chapter 1: IntroductionIntroduction

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Chapter 1 Engineering Mechanics: STATICS

Fifth EditionCopyright 2008 Pearson Education South Asia Pte Ltd

學習目標

工程師如何設計和建造我們使用的設備 ?•Gōngchéngshī rhé sh!"# hé "i$n%$o &'(en sh)y*ng de sh!+!i?

•Engineers ho& to design and +ui,d e-uip(ent that &e use?

工程師在結構體的設計及組合過程之各個!"#$%&學的'()*用&學之%&學+結構設計,-的./0學之1) Gōngchéngshī %$i "iég*u t) de sh!"# ". %/hé gu*chéng %hī g!ge "idu$n dōu %1nn "#ng ,#ué de yu3n,)4

5#ngy*ng ,#ué %hī "#ng ,#ué sh# "iég*u sh!"# "#sh6 de "īch/ 7ué %hī yī

Engineers in the design process and the arious stages o9 a co(+ination o9 structure 9o,,o& the princip,es o9 statics4Statics App,ied :echanics o9 structura, design is one o9 the 9oundations o9 science techno,ogy

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2345

• 工程6*用&學 Gōngchéng y/ y#ngy*ng ,#ué Engineering and App,ied :echanics

• 789:;& nid6n &$ny'uy)n,# <e&tonian graitation

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工程6&學

*用&學

> <=&和>?@的AB

%&學

>C體DEF

G&學

> C體DHG

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%&學

IJKLM及NO工程師H用%&學PQR的EFS程T U設計IJ結構) c3i,i$o "īi! ". t/(6 gōngchéngshī y6ny*ng "#ng ,#ué tuīdBo ch1 de

p.nghéng 9ngchéngsh# ,3i sh!"# c3i,i$o "iég*u4

:ateria,s (echanica, and cii, engineers use statics deried (ateria, +a,ance e-uation to design the structure4

G&學

NO工程師使用G&學PQR的S程TUVW建XCYZ[的\*)

]^工程師_用U`abc的de) t/(6 gōngchéngshī sh)y*ng d*ng,# ué

tuīdBo ch1 de 9ngchéngsh# ,3i 9nī "i$n%h &6 du# d#%h!n de 9Bny#ng4

D3ng7ōng gōngchéngshī %é y*ng ,3i "uéd#ng &!iīng de gu)d$o4o ana,y%e the seis(ic response o9 +ui,dings to cii, engineers use to derie 7inetic e-uations4

Aeronautica, engineers to deter(ine the sate,,iteFs or+it4

工程6*用&學

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fRgh HiI ch1 &!nt. So,ution o9 the pro+,e(

• ijk:的lm)nfop及的C(qr)• L.-īng "# y'u de sh6"64 LiBo"iI su' sh!". de &6,) #t'ng4

• C,ari9y the eisting data4 Jnderstanding physica, syste(s ino,ed4

• f`的st)uo:v*用之'(及S程T)wRxyz{

|}gh~•€6fRgh) HiI"ué de c!,K!4 Li! su'y'u d$i y#ngy*ng %hī yu3n,) ".

9ngchéngsh#4 Du$ ch1 sh#y#t +# y "ing &!nt. sh#"ué hu$ y/ "iI ch1 &!nt.4

• So,ing strategy4 List o9 a,, pending app,ications o9 the princip,es and e-uations4 ra& a sche(atic diagra( o9 Pi toisua,i%e the pro+,e(s and so,utions o9 pro+,e(s4

• ‚ƒ„)…†‡fS程T)ˆ個‰Š‹ŒŽ6oˆ

‚‘Ž’’+“合() 56c! d3F$n4 Sh#%he -6 "iI 9ngchéngsh#4 Mu* g! %hnsh.#ng "iBny$n +#ng y/ su'%u* y6c! +)"i$o 7$n 7$n sh#9'u hé,)4

• Prediction ans&er4 ry to so,ution e-uation4 As a rea,ity chec7 and co(pared &ith predicted ta7en to see &hether it isreasona+,e4

工程6&學

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l”

• :–l––—的+l”:y˜的–lŽ™š1個›œl”žl) Ÿ如 N4;0 和 0400N;0¡¢個l”各:£個:

–l)• 5'ui$o &!i sh6OO%h) de sh# sh6%# y'uy#y# de &!i sh6 cng d# yī g! 9i ,.ng sh6%# i$ng y*u sh64 L#rQN4;0 Dé

0400N;0 Mh! ,iBng g! sh6%# g! y'u s# g! y'ui$o &!i sh64

• E99ectie nu(+er o9 +its R is a nu(+er (eaning9u, digit nu(+er to the right 9ro( the 9irst nonR%ero nu(+er4 orea(p,eQ N4;0 and 0400N;0 these t&o 9igures had 9our signi9icant digits4

• 如¤l”+¥‚¦§¨的Ž_©的:–l的ª«}¬| ‚¦®的¯°)

• Tgu' sh6%# sh# yu c!,i3ng déd$o de %é t de y'ui$o &!i sh/ de duōguB "ing sh*u i$n y c!,i3ng -# de "īngd64

• U9 the nu(+er is (easured it is the a(ount o9 a,id digits &i,, +e ,i(ited to (easuring accuracy

•±²用計³L´Žµ¶·¸¹º的»¼½¾¿

roundingRo99 errorsÀŽÁ§Â4ÃÄ°)• ng ,#y*ng "#su$n"ī sh. +#(iBn %hōng"in +6%h*u de shI r6 &6ch >roundingRo99 errors y) dé %u#d$ %h/n-u! d64

• Vhen using a co(puter aoid the inter(ediate step o9 rounding errors >roundingRo99 errors in order to o+tain(ai(u( accuracy4

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• ^¸和´¸ Wōng"in hé sh."in Space and ti(e

• ^¸—我們oÅÆ的ÇÈÉÊ)Ë¥a˜^¸·¢Ì¸的之Í°ÎÏÐU‚¦) S4U4Ñ–ÒÓ >(Î J4S4Ñ–ÔÓ >9t)

• Wōng"in %h) &'(en su' "1%h6 de sn&éi y/%h*u4 H. yu d#ngy# 7ōng"in %hōng ,iBng diBn "in de %hī ch3ngd6 hu* "6,.

,3i c!,i3ng4S4U4 n&!iQ Gōng ch) >( hu* J4S4 n&!iQ 5īngch) >9t4• Space re9ers to the threeRdi(ensiona, unierse &e ,ie in4 he ,ength is de9ined +y the space or distance +et&een t&o

points is (easured4 SU unitsQ (eters >( or JS unitsQ 9eet >9t4

• ´¸+ÁÕÖ的×Ø¸ÙU‚¦) S4U4及 J4S4Ñ–Ú>s)

• Sh."in sh# y) sh#"i$n de chng96 "i$ngé ,3i c!,i3ng4S4U4 H. J4S4 n&!iQ :iBo >s4

• i(e is the repeat intera, to (easure eents4 S4U4 and J4S4 unitQ second >s4

• >ÛDÜ° >(XsÎ 9tXs 及ÝÜ° >(Xs2Î 9tXs2)• Y.t &!i s6d6 >(Xs hu* 9ts ". "is6d6 >(Xs2 hu* 9tXs24

• he other 9or speed >( X s or 9ts and acce,eration >(Xs2 or 9tXs24

工程6&學

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• 78š1HGaÞ <id6n d# yī y6nd*ng d#ng,[ <e&tonFs 9irst ,a& o9 (otion

• ±ˆ用|ßÌ之&的à和Dœ´Žáâ的Ü°}Èãäå• $ng %u*y*ng y %h.diBn %hī ,# de %'nghé &éi ,.ng sh. ,#%) de s6d6 "ing &éich. +6 +i$n4

• he su( o9 the partic,e as the 9orce used is %ero the speed o9 the partic,es &i,, re(ain unchanged4

• 如¤áâÂæ的HGçè+%é的Ž_©êãë的ìã在%éäG的çè)

• Tgu' ,#%) %u#ch1 de y6nd*ng %hu$ngt$i sh# "#ng%h) de %é t hu# ch.6 de +Boch. %$i "#ng%h) +6d*ng de %hu$ngt$i4

• U9 the initia, state o9 (otion o9 partic,es is stationary it &i,, continue to (aintain the stationary state4

工程6&學

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78šíHGaÞ

• ±ˆ用|ßÌ之&的à和äDœ´Ž_&的à和î|ïßÌ的ðG¦å€ñ)

• $ng %u*y*ng y %h.diBn %hī ,# de %'nghé +6 &éi ,.ng sh. %é ,# de %'nghé dIngy gi %h.diBn de i$n d*ng,i$ng+i$nhu$ ,[4

• he su( o9 the partic,e as the 9orce used is not %ero then the 9orce is e-ua, to the su( o9 the partic,eFs ,inear(o(entu( change rate4

• 如¤ß¦äåŽ&的à和î|ßÌ>ß¦6ÝÜ°之ò)

• Tgu' %h#,i$ng +6 +i$n ,# de %'nghé dIngy %h.diBn -. %h#,i$ng y/ "is6d6 %hī "ī4• U9 the -ua,ity is the sa(e e-ua, to the su( o9 the 9orce o9 partic,e acce,eration o9 its product -ua,ity4 ma F =

工程6&學

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78šÇaÞ

• ¢個ßÌóôõÝ|YS之&的4ö÷îøS÷\)

• LiBng g! %h.diBn +)c) shī"i y du#9ng %hī ,# de d$iBo ingdIng d$n 9ngi$ng ing9Bn4

• he si%e o9 the 9orce app,ied to the other side o9 each o9 t&o partic,es o9 e-ua, +ut opposite in direction4

• ùy¨Ž¥78šíaÞŽ• Mh6y# d$o yu nid6n d# !r d#ng,[

• Ve note that +y <e&tonFs second ,a&

• úôŽûüaýþÿlŽ我們能`a未þÿl)• 5īnc) ru* gIi d#ng y) %hī cnsh6 &'(en néng "uéd#ng &!i%hī cnsh64

• here9ore i9 gien the 7no&n para(eters &e can deter(ine the un7no&n para(eters4

)m/s()kg() N( 2am F ×=

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• \4 國際Ñ–制 >S4U4Ñ– • Gu"# dn&!i %h# >S4U4 n&!i

• Unternationa, Syste( o9 Jnits >S4U4 units

QRÑ–

.本Ñ–

22 m/skg1)m/s1)(kg1( N1 ⋅==

工程6&學

•Hī+In dn&!i

•he +asic unit

•Boch1 dn&!i

•Eport Jnit

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”首縮寫倍級

nanoR n 10-9

(icroR ] 10-6

(i,,iR ( \0R;

7i,oR 7 103

(egaR : 106

gigaR G \0Z

工程6&學

\4 國際Ñ–制 >S4U4Ñ–

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• ùy¨

\ ,+ ^ >\ s,ug >\ 9tXs2

Áß¦表xŽ可§

.本Ñ– QRÑ–

/ftslb1slug1 2⋅=

工程6&學

• 2. 美制Ñ–

• :Ii%h# dn&!i

• JS units

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•角°a˜D θ Y*之部V圓弧Í6圓的半徑¢者之Ÿ•HiBod6 d#ngy# &!i th du#y#ng %hī +69!n yu3n h %hBng y/ yu3n de +$n"#ng ,iBng %hI %hī +),#4

• Ang,e is de9ined as the ratio +et&een the portion corresponding to the arc ,ength _ and the radius4

R

S

=θ

工程6&學

• 3. 角°Ñ– HiBod6 dn&!i Ang,e unit

s

θ

R

• 角° >θ 表xD弳° >rad°l >`•HiBod6 >th +iBosh# &!i "#ng d6 >rad d6shu >`Q

• Ang,e >_ is epressed as radians degrees >rad indegrees >`Q

°= 360rad2π

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( ) ft/s47.1s3600

h1

mi1

ft2!0mi/h1mi/h1

=

=

Ÿ如Ž

工程6&學

4.Ñ–的轉換 n&!i de %huBnhu$n Conersion units

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觀念範Ÿ 1.1

Ñ–的轉換

•1名男â騎!"的Ü°D#Ú 6ÒÓ (m/s))$gÛ

的Ü°+#ö´%Ò& (km/h) '

• 5ī (.ng n3n%) -. %#.ngch de s6d6 &!i (Ii (iBo gōng ch) >(Xs4 Y)ng&!n t de s6d6 sh# (Ii iBosh. ") gōng,)>7(Xh?

• A (an riding a +icyc,e speed o9 (eters per second >( X s4 Vi,, his speed is a 9e& 7i,o(eters per hour >7( X h?

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• St ng,K! Strategy

• 1Ò&D \000ÒÓŽ1ö´D 0 V( ^ ;00 Ú)我們能使用¡)Ñ–轉換U`aÁ 7(Xh 表x之Üñ)

• 5ī gōng,) &éi \000 gōng ch) yī iBosh. &!i 0 9n%hōng ^ ;00 (iBo4 V'(en néng sh)y*ng %h!idn&!i %huBnhu$n ,3i "uéd#ng y) 7(Xh +iBosh# %hī s6,[4

• ne 7i,o(eter is \000 (eters one hour 0 (inutes ^ ;00 seconds4 Ve can use these units todeter(ine the conersion rate in 7( X h indicate it4

觀念範Ÿ 1.1¿ëÀ

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•fƒ HiId3 Ans&er

km/h6.12

h1

s3600

m1000

km1 m/s6m/s6

=

=


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•*習h Li$n. t. Eercises

•1名男â騎!"的Ü°D#Ú 10 + (ft/s))$gÛ的 Ü° ,-./01 +#ö´%3'

• 5ī (.ng n3n%) -. %#.ngch de s6d6 &!i (Ii (iBo \0 ch) >9tXs4 Y)ng&!n t de s6d6 >(iXh sh# (Ii

iBosh. ") ,ī?• A (an riding a +icyc,e speed o9 \0 9eet per second >9t X s4 Vi,, his speed >(i X h is a 9e& (i,es per

hour?

ƒ„ 6.!2 mi/h)


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範Ÿ 1.2

4&Ñ–的轉換

(ÿ56本 )Fàn! 1."

#$! d$n%&i de 'hunhuàn(C$n*u& +&,-n)

Ea/pe 1."

0ressure unit conersion (See tet,oo+s)

範Ÿ 1.3

¥S程T`aÑ– #2u f$ngch3ngsh! 4u3d!ng d$n%&i

The decision ,* the e5uation unit

(ÿ56本 )

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787設ß¦Dm\ 及 m2 8¸ÙÏÐ r 的¢ßÌ¸之×&

D•<id6n "iBsh! %h#,i$ng &!i (\ ". (2 -iI "i$ngé "6,. r de ,iBng %h.diBn "in %hī %h*ng,# &!i

•<e&ton assu(ed that the -ua,ity o9 the graitationa, 9orce +et&een the (\ and (2 and the spacing o9 the t&o partic,es is r

>\4\

2

21

r

mGm F =

789:;&

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•#D9:;&9l)T· r —的+¥ßÌ:;<的ÏÐ)

•G &!i &$ny'uy)n,# ch3ngsh64 Sh# %hōng r %h) de sh# yu %h.diBn %h# -i īn de "6,.4•G is the graitationa, constant4 Vhere r re9ers to the distance 9ro( the partic,e to the center o9 the sphere4

789:;&

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•=>Z;ä+?ß;體Žø@能使用T >\4\ UA³ß¦m之C體úZ;×&ÝÜ°oB@的×¦Ž•Suīr3n d#-i +6sh# "1n%h# -it) d$n réng néng sh)y*ng sh# >\4\ L3i g1su$n %h#,i$ng ( %hī &6t) yīn d#-i %h*ng,# "is6d6su' chBnshng de %h*ng,i$ng

• A,though the earth is not a ho(ogeneous sphere +ut sti,, use the 9or(u,a >\4\ to esti(ate the &eight o9 the o+"ectFs(ass ( due to the EarthFs graitationa, acce,eration generated

>\42

• >· mE DZ;ß¦Ž r DZ<:C體之ÏÐ)•Y.%hōng ( &!i d#-i %h#,i$ng ( &!i d# īn %h# &6t) %hī "6,.4

•Vhere ( is the EarthFs (ass ( is the geocentric distance to the o+"ect4

2 $

r

Gmm F =

789:;&

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•±1個C體的×¦+C1的ˆ用&´Ž¥ôB@的ÝÜ

°DE×&ÝÜ°)™78šíaÞ—RŽW = ma FG¥T (1.2) 我們’¨×&ÝÜ°+

•ng yīg! &6t) de %h*ng,i$ng sh# &éiyī de %u*y*ng ,# sh. yu c) chBnshng de "is6d6 "i$o%u* %h*ng,# "is6d64 Cngnid6n d# !r d#ng,[ %h)ch1V ^ (ab ér yu sh# >\42 V'(en 7$n d$o %h*ng,# "is6d6 sh#

•Vhen the &eight o9 an o+"ect is the on,y 9orce the resu,ting acce,eration is ca,,ed graitationa, acce,eration4 Pointed outthat <e&tonFs second ,a& V ^ (ab and +y the 9or(u,a >\42 &e see that the graitationa, acce,eration is

>\4;2

$

r

Gma =

789:;&

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• }HEI之×&ÝÜ°JD g = Z48\ (Xs2ŽGZ;半徑

JD R E Ž¥ E- >\4;Ž可§•Hing hBi p.ng(i$n %hī %h*ng,# "is6d6 "# &!i g ^ Z48\ :Xs2 ér d#-i +$n"#ng "# &!i TE yu E- >\4; WI dé

•he graitationa, sea ,ee, recorded as g ^ Z48\ ( X s2 and re9erred to as EarthFs radius TE +y the E- >\4; can +eo+tained

2

$$

gRGm =

789:;&

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úôŽÐZ< r 之K的×&ÝÜ°D•5īnc) ,. d# īn r %hī ch/ de %h*ng,# "is6d6 &!i

•hus 9ro( the graitationa, center o9 the earth is r p,ace

>\4=

2

2

$

r

R g a =

789:;&

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• úDC體×¦ W = maŽoÁÐZ<ÏÐ r 之C體×¦D•5īn&!i &6t) %h*ng,i$ng V ^ (a su'y) ,. d# īn "6,. r %hī &6t) %h*ng,i$ng &!i

•ecause the &eight o9 the o+"ect V ^ (a so the &eight o9 the geocentric distance r 9ro( the o+"ect o9 the

>\4@2

2

$

r

Rmg W =

789:;&

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在HEI >r = R E ŽC體×¦Á>ß¦表x´ŽDÁLM

ÑNO•M$i hBi p.ng(i$n >r ^ TE &6t) %h*ng,i$ng y) -. %h#,i$ng +iBosh# sh. &!i y)i$ "iBndn gun#Q

• At sea ,ee, >r ^ TE +ody &eight is represented +y its -ua,ity as the 9o,,o&ing si(p,e re,ationshipQ

>\4mg W =

789:;&

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• C PQ在HEI× \= o%) \ o% >ounces ^ \ ,+ HE I的×&ÝÜ°D g ^ ;242 9tXs2)_ C PQ的ß¦Á

s,ug 表xD何'• C .ng -i3n %$i hBi p.ng(i$n %h*ng \= o%4\ % >ounces ^ \ ,+ hBi p.ng(i$n de %h*ng,# "is6d6 &!i g ^ ;242 tXs24

Mé C .ng -i3n de %h#,i$ng y) s,ug +iBosh# &!ihé?

• CRc,a(p heay \= o% at sea ,ee,4 \ o% >ounces ^ \ ,+ sea ,ee, o9 acce,eration o9 graity is g ^ ;242 9t X s24 he-ua,ity o9 the CRshaped c,a(p to s,ug indicate &hy?

觀念範Ÿ 1.4 (ë )

×¦及ß¦

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觀念範Ÿ 1.4 (ë )

St

•我們RSTÄa % PQ+ªUV×)>WŽ我們可Á使用T (1.6)ŽU³R©的ß¦+ªUXYZ)

•V'(en +#1 in -u!d#ng C .ng -i3n sh# duōshBo +$ng %h*ng4 T3nh*u &'(en 7Iy) sh)y*ng sh#>\4 L3i su$nch1 t de %h#,i$ng sh# duōshBo sh) , gé4

•Ve (ust 9irst deter(ine ho& (any CRc,a(p pounds4 hen &e can use 9or(u,a >\4 to ca,cu,ate its(ass is (uch Shi Lage4

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fƒ

觀念範Ÿ 1.4 (ë )

slug0.0272ft/s32.2

lb!7.0

lb0.!7&'16

lb1 &'14&'14

2 ===

=

=

g

W m

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*習h

•C PQD 04;ZN 7g)HEI的×&ÝÜ°D g ^ Z48\(Xs2)_ C PQ在HEI的×¦Á78表xD何'•C .ng -i3n &!i 04;ZN Wg4 DBi p.ng(i$n de %h*ng,# "is6d6 &!i g ^ Z48\ :Xs24 Mé C .ng -i3n %$i hBip.ng(i$n de %h*ng,i$ng y) nid6n +iBosh# &!ihé?

•CRshaped c,a(p o9 04;ZN 7g4 Acce,eration o9 graity at sea ,ee, g ^ Z48\ ( X s24 he CRshaped c,a(psea ,ee, in &eight epressed in <e&ton Vhy?

ƒ„ ;48Z <

觀念範Ÿ 1.4 (ë )

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範Ÿ 1.5

計³C體的×¦

6!suàn %7t8 de 'h9ngiàng

Cacuate the %eight of the o,4ect

(ÿ56本 )

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Fifth Edition

$ÿ56本š 12[\]的^_Y)ng cnyu! 7!+In d# \ %hng g!ng i3ng# de n!irng

See Chapter \ tet+oo7 content (ore detai,

chapter 01 - 導言

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