1.修饰的词不同。同位语从句前的先行词比较有限，且大部分都是抽象名词;定语从句的先行词可以是比较复杂的内容，可以即包括人又包括物。
2.从句的作用不同。同位语从句是用来解释前面的名词的，而定语从句则是修饰的作用。
3.关系词的作用不同。同位语从句中that是连词，不充当任何成分，但是不能省略。而定语从句中that是充当一定成分的，在某些情形下是可以省略的。
翻译示例：
Manypeoplehavestoppedbuyingit,______________(尽管一再保证这种产品是安全的).
2.尽管可以用一个介词短语，despite，后面应该接名词短语
3.同位语从句：assurance后面接一个同位语从句对“保证”进行说明。
答案：despiterepeatedassurancesthattheproductissafe
1.Theyreceivedorders___________theworkbedonerightaway.
A.whichB.thatC.whereD.when
2.Thenews___________hewaskidnappedsurprisedusgreatly.
3.Informationhasbeenputforward_________moremiddleschoolgraduateswillbeadmittedintouniversities.
4.Threedayslater,wordcame________ourcountryhadsentupanotherman-madesatellite.
A.whichB.whenC.thatD.where
5.Alongwiththeletterwashispromise__________hewouldvisitmethiscomingChristmas.
A.whichB.thatC.whatD.whether
6.Thereason__________thelittleactresshasbeensuchasuccessis__________sheisbothcleverandhard-working.
A.why,whyB.why,thatC.that,becauseD.for,because
7.Awarmthoughtsuddenlycametome__________Imightusethepocketmoneytobuysomeflowersformymother'sbirthday.
8.There’safeelinginme__________is-notever.
A.whichwe’llneverknowwhataUFO
B.ofwhichweneverknowwhataUFO
C.whenweneverknowwhataUFO
D.thatwe’llneverknowwhataUFO
9.I'vecomefromthegovernmentwithamessage__________.
A.ifthemeetingwillbeheldtomorrow
B.whetherthemeetingwillbeheldtomorrow
C.thatthemeetingwon'tbeheldtomorrow
D.whichthemeetingwon'tbeheldtomorrow
10.Thethought__________.
A.ofwhichhefailedintheexamworriedhim
B.whichhefailedintheexamworriedhim
C.whathemightfailintheexamworriedhim.
D.thathemightfailintheexamworriedhim.
答案及解析：
答案：1.B2.D3.D4.C5.B6.B7.C8.D9.C10.D
1.同位语从句。that引导从句作orders的同位语，解释orders的具体内容。主句：Theyreceivedorders.orders内容如下：Theworkbedonerightaway.
2.同位语从句。that引导从句作news的同位语，解释news的具体内容。主句：Thenewssurprisedusgreatly.news的内容如下：Hewaskidnapped.
3.that引导从句作information的同位语，解释information的具体内容。主句：Informationhasbeenputforward.information的具体内容为：Moremiddleschoolgraduateswillbeadmittedintouniversities.
4.that引导从句作word的同位语，解释word的具体内容。主句：Threedayslater,wordcame.
word的具体内容为：Ourcountryhadsentupanotherman-madesatellite.
5.that引导从句作promise的同位语，解释promise的具体内容。主句：Alongwiththeletterwashispromise.promise的具体内容为：HewouldvisitmethiscomingChristmas.
6.此题为故意考查大家是否能辨别同位语从句与其他从句使用that的区别而设置。并不考查同位语从句。第一空为定语从句，why和that都可引导定语从句修饰thereason;第二空为表语从句，根据句意“……的理由是”只能选择that，如果because或why就意为“……是因为”句意不通，所以，答案为B。
7.that引导从句作awarmthought的同位语，解释awarmthought的具体内容。主句：Awarmthoughtsuddenlycametome.awarmthought的具体内容为：Imightusethepocketmoneytobuysomeflowersformymother'sbirthday.
8.同位语从句thatwe’llneverknowwhataUFOis-notever作afeeling的同位语，解释afeeling的具体内容。that连接同位语从句时，只起连接作用，不作从句的任何成分。
9.that引导从句作amessage的同位语，解释amessage的具体内容。amessage的具体内容为：Themeetingwon'tbeheldtomorrow.
10.that引导从句作thought的同位语，解释thought的具体内容。主句：Thethoughtworriedhim.thought的具体内容为：Hemightfailintheexam.
