氧气瓶内的气体不能全部用尽，应留有( )MPa的余压。
A．0.4～0.6
B．0.3～0.5
C．0.3～0.4
D．0.1～0.3
参考答案：D
根据句意及汉语提示完成句子。
1. Tony, you'd better pay attention to your ______(书写) when you do your homework.
2 .________ (无论在哪里) you are, your parents will missyou very much.
3. How much progress have you_______(达到) since you joined the English club?
4. Can you tell me how to improve my English _______ (水平), Miss Green?
5. Getting good grades_______ (需要) hard work andcarefulness.
