1,--When will the lecture begin?

1,--When will the lecture begin?
--When the students______.
A have sat 学生们已经做过坐的动作.不妥!
B sat down 学生们坐了下来.不妥!
C will sit 学生们将要做坐的动作.不妥!
D are seated：
seat是及物动词,后面必须带宾语（the students seat themselves 学生们使自己坐好）或者用被动（the students are seated学生们就座 ）
2,First,it is important to recognize what kind of person you are and whitch special qualites make you ______from everyone else
make you + different（形容词补足语）,使你具有与...不同的特征
3,It is not unusual that rain ____ without stopping these days of the year.
It is not unusnal是指现在不同寻常,主语从句中的rain一定是现在总在下而不是正在下也不是已经下锅,所以要用一般现在时.
4,The trouble she is having ___the computer is so great that she doesn't know whom to turn___
答案：B
trouble与介词with搭配表示“...有故障”；turn to 意思是“求助于”,whom在这里是宾语提前,也就是turn to whom,“求助于谁”,但是疑问代词只能放在turn to前而不可以放在后.