They found the lecture hard ___________.

They found the lecture hard ___________.
A、to be understood
B、to understand
C、being understood
D、understood
【正确答案】：B
【题目解析】：find sth+形容词+(for sb)to do 句型。这里不能选A,to be understood ,因为这个句型，不定式to do 的逻辑主语是sb.只不过省略了for sb。