There was no sign _______ they had died from diseases such as bird flu - the main worry in such cases. Among the theories was _______ a truck had collided(碰撞)with the crowd.
第二节语法和词汇知识(共l5小题;每小题l分,满分l5分)
从A、B、C、D四个选项中,选出可以填人空白处的最佳选项,并在答题卡上将该项涂黑。
We_____last night,but we went to the concert instead.
A.must have studied B.might study
C.should have studied D.would study