题目内容：

根据句意和汉语注释，在答题卡标有题号的横线上，写出单词的正确形式。

1.The teacher showed great ____________ to jump into the river to save the poor boy.  (勇气)

2.In the northern part of China, the lake is as ________________ as glass in winter because it isturned into ice. (光滑的)

3.When you try to get a good job, you will be at a big _____________ if you don’t go to a gooduniversity.（劣势）

4.China took action to search for the missing plane---MH370 __________ after getting the news. (立即)