Please complete the following sentences according to what has been given.
1．_________________________（直到他完成使命）did he realize that he was seriously ill.
2.Contrast may make something appear _____________ (比单独看时更漂亮).
3.If this can’t be settled reasonably,it may be necessary to ____________（诉诸武力）.
4.The concert usually takes place at the People’s Square,__________________（观众坐在地上）.
5.The sports meeting originally due to be held last Friday ______________（最后因天气不好而取消了）.