It was because he was ill we decided to return home.A. whyB. thatC. whenD. where

问题补充：

It was because he was ill we decided to return home.

A. why

B. that

C. when

D. where

答案：

A. why

(答案→)B. that

C. when

D. where

解析：考查强调句：结构是：it is /was+被强调部分+that/who+…，其最大的特点是把it is/was…that/who…去掉，句子仍然成立。强调的是原因状语：because he was ill，句意：是因为他生病了，我们才决定回家的。选B。