If my lawyer ______ here last Friday, he _____ me from telling the truth.

At present, what _____ most heavily on American people is the terrorist accident(恐怖事件).

He didn’t listen to the teacher carefully, __________, he couldn’t answer the questions.

As is often pointed out, knowledge is a two-edged weapon which can be used_____________for good or evil

The students ________ two groups to play the game yesterday afternoon.