在火场上使用空气呼吸器时，佩戴者在听到汽笛报警后应及时撤离作业现场。
参考答案：对
腭裂发生于
A．胚胎第1～3周B．胚胎第4～6周C．胚胎第5～7周D．胚胎第8～12周E．胚胎第13周以后
Directions:
Tom, your classmate, has won English Speaking Contest sponsored by CCTV. You watched the con-test at that time and you are very proud of him. Now, you are going to write him a letter to convey your congratulations on his success.
Write your letter in no less than 100 words. Write it neatly on ANSWER SHEET 2.
Do not sign your own name at the end of the letter; use" Li Ming" instead.
Do not write the address.
