1 . Had I known the party was so boring, I wouldn’t have come. It __________ (prove) a failure. (所给词的适当形式填空)

2 . I was so proud when my team ________ (win) the ice hockey competition.（所给词的适当形式填空）

3 . He ________ (sharpen) his knife in order that he cut meat easily . （所给词的适当形式填空）

4 . It suddenly ________ (occur) to him that he had an important meeting to attend the next morning. (所给词的适当形式填空)