根据句意及汉语提示，用短语的恰当形式完成下列句子，并将正确答案写在答题卡相应的位置。
小题1:All the children _________________ ( 应该 )study hard.
小题2:______________ ( ……的数量 ）the students in our school is 1400.
小题3:_________（ 毫无疑问） that it is the most expensive to go by plane.
小题4:The room is too noisy, please _____________（调低音量）the radio.
小题5:How do you _________（ 处理 ）the waste water from the factory?
