高三英语选择题（解释一下为什么）

Question

we have been informed that he had done __ visits were essential by eleven o'clock last night.
A all B what C that D all that

Answer 1

选B。
主体句式中that引导了第一个宾语从句"he had done __ visits were essential by eleven o'clock last night" ,
选B就会使这第一个宾语从句里又套了第二个宾语从句"__visits were essential " ,
而what在这第二个宾语从句里做主语，成立。
选A是使第一个宾语从句中包含一个定语从句，修饰all visits，但这样定语从句中就会缺少主语（were前面），而在定语从句中主语是不能省略的，不成立。
选C两个错误，1.that做指示代词时只能修饰单数名词 2.定语从句中仍然缺少主语
选D句式混乱，改为......he hade done all visits that were essential......则正确，这时all visits做宾语，that were essential成为定语从句修饰宾语，即做宾补。

Answer 2

选b
排除法选其他的话，从句中有两个谓语动词，不合理

Answer 3

选B，what。
句意判断：我们已经被告知到昨天晚上7点之前，他已经做过了必要的访问/视察。
选项辨析：
①如果用A、C、D中的某个，原句需变为：
We have been informed that he had done 【all the】_ visits【that】 were essential by eleven o'clock last night 。
因为，直接用all,少了定冠词；而且，句子结构混乱而导致错误：that宾语从句中，出现了两个非并列的谓语动词【had done 】和【were essential 】。
用that作指示代词时，需修饰单数名词，直接错误；
用all that,all 是不定代词，应该是先行词，与visits重复，错误。
② 用what，what visits were essential =【all the】 visits【that】 were essential 。

Answer 4

B。宾语从句。这里what=the things that

Answer 5

we have been informed that he had done __ visits were essential by eleven o'clock last night.
A all B what C that D all that
答：我怀疑题目有误，这个visits有点莫名其妙！搜索网络，找不到此题。去掉它，句子才有意义：
We have been informed that he had done ______ were essential by eleven o'clock last night.
A all B what C that D all that
答：B
译：有人告诉我们说他在昨天晚上11点之前就已经做好了那些重要的事情。
析：从句意上BD都可以。但是what=the things that..., 从句谓语可以用were,但all表“事情”时，为单数，如将were改为was,则BD都可以。

Answer 6

b