—Did you have any difficulty catching yesterday’s lecture?
—No. The professor spoke very clearly to make his speech easy .
A. understood
B. understanding
C. to be understood
D. to understand
网友回答
A. understood
B. understanding
C. to be understood
D. to understand
解析：这题考查句型:make+宾语+adj+to do句型，这里的不定式是主动表示被动。句意是：教授说的很清楚使他的演讲很容易理解。选D。