The chairman thought necessary to invite Professor Smith to speak at the meeting.A. that

问题补充：

The chairman thought necessary to invite Professor Smith to speak at the meeting.

A. that

B. it

C. this

D. him

答案：

A. that

(答案→)B. it

C. this

D. him

解析：此题考查学生对it的掌握和运用能力。it作形式宾语,代替后面的不定式to invite Professor Smith to speak at the meeting。that指代前面已发生或者提到的事,或者用于对比作远指代词;this指代将要做的事或用于对比表近指。this和that在句中都有自己明确的意思。