1.It was essential________________(在截止日期前寄回申请表)。

    2.I went to see William,__________________(结果发现他前两天已经走了)。
    
    3.He flatly contradicted the audience was instantaneous; no sooner ____________________(讲演刚结束，听众就爆发了热烈的掌声)。
    
    4.Should it rains,____________________(农作物就得救了)。
    
   1.that the application forms be sent back before the deadline
    
    2.only to learn that he had left two days before
           
    3.had the speaker finished than the audience burst into applause
    
    4.the crops would be saved