he was ill I was expected to take his place greatly surprised me for I didn't have much

问题补充：

he was ill, I was expected to take his place greatly surprised me

for I didn have much working experience.

A. If

B. That if

C. That

D. If that

答案：

A. If

(答案→)B. That if

C. That

D. If that

解析：That引导的是主语从句，而 if 从句是that主语从句中的条件状语。