适当形式填空（共5分）
小题1:He promised his father that he _______________(give) up smoking this year.
小题2:I did what I can _____________(help) my brother with his English study.
小题3:The accident suddenly_______________(happen) while the lights were changing to red.
小题4:Everyone agreed that we should stop the factories ______________(pour) the dirty water into the river.
小题5:They think you’d better not ____________(join) this club this year.
小题1:would give
小题2:to help
小题3:happened
小题4:pouring
小题5:join
题目分析：
小题1:句意：他对他的父亲承诺说今年他会戒烟。根据句意应该用过去将来时，故填would give。
小题2:句意：我做了所有我能做的来帮助弟弟学英语。本句中to help 是一个目的状语。
小题3:句意：在交通灯即将变红时，事故突然发生了。根据while 后的句子所用的时态我们可知本句应用过去时，故填过去式形式。
小题4:句意：大家都同意我们应该阻止工厂把脏水倒入河流。stop sb./sth. from doing sth.阻止某人做某事或阻止某事发生。故用-ing 形式。
小题5:句意：他们认为你今年最好不要参加这个俱乐部。had better do sth. 最好做某事。故用动词原形。