正压式空气呼吸器的使用方法:使用时间:在中等呼吸强度(30L/min)呼吸时,使用时间不宜超过(),
A.20min
B.30min
C.40min
D.60min
参考答案:B
Read and complete. 将每组对话补充完整。
1. A: you?
B: I am fine, thanks.
2. A: Kim?
B: She is in the gym.
3. A: books are there?
B: Five.
4. A: What is five and ninety-five?
B: It's .
5. A: She is behind Jenny.
B: Jenny is her.
关心学习是班主任专业化的核心内容。