解释一下为什么？最好有关键性词组搭配。

1.In 1778,Dr Banks was selected_____president of_____Royal Society,_____ position his father had held for 10 years.
A./ / a B./ the a C.the / a D. the the the
KEY:B
其原因是：第一空表示独一无二的职位，不加冠词；第二空，普通名词构成的专有名词，要加定冠词；第三空，泛指某一职位或岗位，用不定冠词。

2.Success_____measured not so much by the position that one has reached in life as by the obstacles which he has overcome while trying to succeed.
A.is to be B.is being C.has been D. is able to be
KEY:A
这里是一个时态的固定表达方式“be to do”，表示一个将来的必然结果，或安排要进行的动作。
3.We need a chairman_____.
A.for whom everyone has confidence B.in whom everyone has confidence
C.who everyone has confidence of D.whom everyone has confidence
KEY:B
这是一个定语从句，意思是每一个人都对其信任的主席，所以用have confidence in sb.
4.-The education system rather than the teachers_____to answer for the overburden on the students.
-I agree.I hope the reform being carried out in our country at present will bring about the_____results.
A.are;desired B.is;desired C.are;desiring D.is;desiring
KEY:B
这里涉及的是1，主谓一致，主语中有rather than等短语时，谓语动词的人称和数与前面一致。2，分词作定语，过去分词表示被动或完成，这里是被动的意思。
5.I wot't think_____of him because of his shortcomings. He is a good boy after all.
A.too much B.little C.any less D.any more
KEY:C
这里用到一个固定短语think of sb.“认为某人怎样”。原句子的意思是“我不因为他的缺点就对他有什么不敬”。
6.Professor Green's lectures usually ran over a fifty-minute period,_____none of his students even objected as they found his lectures both informative and insteresting.
A.or else B.but yet C.and yet D.somehow
KEY:C
这里是一个连词使用和转折副词搭配的问题。答案B有重复之感，其它的更不合适。