Mr. Smith didn’t go to the party because he had a lot of experiments .A. doB. didC. doneD.

问题补充：

Mr. Smith didn’t go to the party because he had a lot of experiments .

A. do

B. did

C. done

D. to do

答案：

A. do

B. did

C. done

(答案→)D. to do

解析：考查不定式的用法：句意：史密斯先生没有去参加晚会,因为他有许多实验要做。Have sth to do，有…事情要做，这里不定式做后置定语，修饰experiments，选D。