He was very nervous when he was asked to make an _______ speech.

问题描述:

He was very nervous when he was asked to make an _______ speech.
A:tedious
B:boring
C:impromptu
D:impulse

选c
意思是当他被要求做即兴演讲时他非常紧张.
impromptu speech就是即兴演讲