A robot-arm will hold the telescope___the astronauts to repair it A for B so that

题目

A robot-arm will hold the telescope___the astronauts to repair it A for B so that
请问选择哪一个,这两个答案分别什么时候用,for后面叫什么句

答案

A for 引导的介词短语作will hold的目的状语,正确.而 so that是从属连词,后面必须接句子.