it seemed certain that their plane would crash

it seemed certain that their plane would crash At one point,it seemed certain that their plane would crash. At one point,it seemed certain that their plane would crash 新概念二43课It seemed certain that the plane would crash是不是主语从句?如 It seemed certain that the plane would crash为什么不是certainly呢? it seem certain that their plane would crash 为什么不这么说 it seem it seem certaim that their plane would crash 请问 it指的是什么 如果指的 it seemed certain that 有关形式主语有些句子里可不可以不用形式主语,比如这个It seemed certain that their plane it seemed certain that she would be first ship home 联系动词 是系动词吗 后边加形容词 it seem certain that their plane would cra It seems/seemed certain that...Byrd now knew that he would .