题目内容：

the scientists needed to do a series of scientific experiments____his new theory.
A.on which to base B,to base on which C which to base on D which to be based on

优质解答

A base sth on sth 把.建立在.的基础上
把他的新理论建立在一系列科学实验的基础上

追问：

为什么不选C

追答：

介词常提前，这是习惯用法，肯定对的