单项选择题
A.happened
B.were happened
C.was happened
D.had happened
单项选择题 () ten minutes earlier, you wouldn't have missed the train.But you were late.
单项选择题 —How are their talks going on Have they reached any agreement —They only seemed to have agreed to set another date for () talks.
单项选择题 Although he knew little about amount of work done in the field, he succeeded () other more well-informed experimenters failed.