1.worry about 担心；担忧

例句:You don't have to worry about me. I'm a good swimmer.
不用担心我。我水性很好。

2.calm down 平静下来；冷静

例句:Calm down for a minute and listen to me.
你安静一会儿，听我说。

3.life jacket 救生衣；救生背心

例句:Inflate your life jacket by pulling sharply on the cord.
猛拽绳扣使你的救生衣充气。

4.look out 小心

例句:What are the symptoms to look out for?
有哪些症状需要注意？