1 I don’t think he could have done so much homework last nig

1 I don’t think he could have done so much homework last night,____?
A.do I B.could he C.has he D.did he
选D B为什么不行呢
2 It’s obvious that the Beijing Olympic Games ______ a great success.
A.kept B.showed C.proved D.remained
选C B为什么不行呢
3 –What do you think of the manager of your company?
-Oh,he is _________ manager who’s pleasant to work with.It’s ______ pleasure to work with him.
A.the; a B.a; a C.a; the D./; a
选B 第一个空后不是有定语修饰吗?为什么还要用a
4 Beijing made its decision to cancel the May golden week of Guangdong ______ on a thorough consideration.
A.to base B.basing C.based D.having based
选C 为什么
5 –We all wonder _________ the relationship between France and China is good again now?
A.why it is that B.why it is C.that it is why D.it is why
选A 为什么?B不行么?
6 The population of the village near the sea,______ are making their efforts to develop economy of their own.
A.nearly seventy percent of which depend on fishing
B.of which nearly seventy percent depends on fishing
C.nearly seventy percent of whom depends on fishing
D.of whom nearly seventy percent depend on fishing
为什么 选别的不行么?

很赞赏上面八位的热情.但可惜都没真正弄懂.
1,COULD/MUST+HAVE +过去分词表示猜测时,其反意问句要把它还原成事实再选择.这时有两种情况,一,用一般过去时（通常带有表示过去的时间）例如,HE MUST HAVE COME BACK LAST NIGHT.还原成事实就是 HE CAME BACK LAST NIGHT.选择TAG QESTION就是DIDNT HE?ER 二,用现在完成时.如 ,HE COULD NOT HAVE COME BACK.还原成事实就是.HE HAS NOT COME BACK.选择TAG QESTION就是HAS HE?再如：I THINK YOU MUST HAVE KNOWN HIM FOR A LONG TIME ,HAVENT YOU?I DONT THINK HE COULD HAVE BEEN ILL YESTERDAY,WAS HE
第二题
B.showed 意思是显示,表明 C.proved 是证明是.当然选C
3定语从句修饰的可以是特指的词也可以是类指的词,看意思.如HE SHOWED ME THE BOOK THAT HE BOUGHT YESTERDAY.他给我看昨天买的那本书（只买一本）.HE SHOWED ME A BOOK THAT HE BOUGHT YESTERDAY.他给我看昨天买的一本书（不只买一本）,因为在一切共事合作愉快的不只一个经理吧?就好似HE IS A TEACHER WE ALL LOVE 一样.所以第一空用不定冠词A.第二空也用不定冠词A是因为PLEASURE作一件愉快的事解时是可数名词,类似用法还有SUCCESS,FAILURE等如THE MEETING IS A SUCCESS.
4,有些词组成的词组如BE FACED WITH（面临.）/ BE EXPOSED TO（暴露于）BE BASED ON（基于.）等与汉语相差太远,如果从词性入手再分析其逻辑主语中国学生难理解.这样记好了：这些词组如果用来做谓语就保留BE动词,做定语,或状语则省去BE.如FACED WITH A CRITICAL CHOICE,HE TURNED TO HIS TEACHER.（由于面临关键的选择,他求教于老师）THE REPORT,BASED ON THE INVESTIGATION,WAS QUITE ACCEPTABLE.
5特殊疑问句的强调句式是：疑问词+IS/WAS +IT +THAT +其他如,WHEN DID HE COME HERE =WHEN WAS IT THAT HE CAME HERE?（THAT不能省略）/WHY ARE YOU WITH HER HERE =WHY IS IT THAT YOU ARE WITH HER HERE 如改为宾语从句则用陈述句词序.TELL ME WHY IT IS THAT YOU ARE.
6POPULATION作人口解是单数,作（某地区）的所有的人解是复数.这里是后者.这样就可以不考虑B和C两项,另外作人口解是物,用WHICH 作（某地区）的所有的人解是人,用WHOM（做介词宾语）,再如,HIS FAMILY,WHICH IS A BIG ONE,IS VERY POOR.HIS FAMILY ,WHO ARE ALL FOOTBALL-LOVERS ,ARE WATCHING A MATCH.