1. uncertain 的用法

　　2. set off/out (出发)

　　3. in the air (在空中)

　　4. in a short while (过了一小会儿)

　　5. be uncertain about/of (对...不确定)

　　6. in (one's) search of (寻求)

　　7. in a hurry (匆忙)

　　8. bring up (抚育; 呕吐)

　　9. play the piano (演奏钢琴)

　　10. at the very beginning (就在刚刚开始)

　　11. a period of several weeks (在好几周期间)

　　12. put on a play (上演戏剧等)

　　13. at the age of 15 (在15岁)

　　14. A is recognized as B. (A 被认作B。)

　　75. A is known as B. (A以B闻名。) → as作'当作, 担任, 以......解。

　　16. of this kind (此类) [of this kind =this kind of]

　　17. the contributions to ... (对...的贡献)

　　18. as if 的用法