12.Read the text a second time and you will probably know what the principle ______ a hovercraft works.

问题描述:

12.Read the text a second time and you will probably know what the principle ______ a hovercraft works.
A.is on that
B.has on which
C.is on which
D.on which

D.D是错的C what the principle is是know的宾语从句,又用了on which引导了 principle 的定语从句那“is”是不是可以放在最后变成 what the principle on which a hovercraft works on is?不可以放在最后。因为what the principle is 是整体的一个句子,不能拆开,否则会引起混乱的。不是定语从句紧跟先行词吗?在为了避免引起混乱的时候,语法上就用“割裂定语从句”来表达,正如本题。