请帮我解释下列英语问题.

题目

请帮我解释下列英语问题.
1 He made another wonderful discovery,___of great importance to science.
A which i think is
B which i think it is
C which i think it
Di think which is
为什么选择A．
2The wolves hid themselves in the places___couldn't be found.
A that B where C in which D in that
为什么选择A
3 Is this the plane___he came to New York?
A which B by which C that D in which
为什么选择B
4 She likes to use words___is clear to him.
A of which the meaning
B of which meaning
C whose of meaning
D meaning of which
为什么选择A
5 He hend me several books,___were very good.
A five of which
B of which
C which of five
D five
为什么选择A．

答案

1,从句中,which作i think的宾语,和it重复了,不要it
think sth {of +名词
名词对应的形容词 which充当了这里的sth
2,又先行词places是定语从句,只有abc
a作疑问代词
b相当于c疑问副词
从句中少的是主语用a
3,定语从句,原因同上,先找先行词,plane,
by表使用的交通工具
且特点,无定冠词
如果用in要有定冠词.
4,也是定从,原因同上,
顺过来是the meaning of which is选项的原因,你就能知道了
5定从
用先行词代which再顺过来,就是,five of the books were
选项的原因亦显而易见……