在过滤操作中,若维持操作压强不变,这种操作称为()。
A、恒速过滤
B、真空过滤
C、离心过程
D、恒压过滤
参考答案:D
If the party is in the morning, Mr. Gao _______ come. He will have a drama show for the elderly. [ ]
A. can't
B. couldn't
C. doesn't
D. isn't
遥控器为什么不起作用?