词型转换：用括号中所给单词的适当形式填空。(共5小题；每小题2分，共10分）

小题1:The bus is ________ (crowd) . Let’s get on it .

小题2:I won’t believe in you unless you tell me the ________ (true).

小题3:Kangaroos are playful and polar bears are __________ (fur).

小题4:You are supposed to type ________ (quick) when you are chatting online.

小题5:Take the elevator to the _________ (nine) floor, you can find it.

汽化即介质发生相变，其特点是（）。

A.体积将骤然增大数十倍

B.温度将骤然增大数十倍

C.瞬间系统内压力将突增

D.可能危及设备及人身的安全