可用推拉注射器栓塞的方法检查下图装置的气密性．当缓慢推活塞时，如果装置气密性好，可观察到（ ）
| A．长颈漏斗内液面上升 | B．瓶中液面上升 |
| C．长颈漏斗下端口产生气泡 | D．注射器内有液体 |
相关试题
This is my beautiful school is near the famous library.
| A． | where | B． | which | C． | who | D． | when |
--- Can you tell me ______ on the Internet? --- OK, mum.
| A． | how can I use QQ | B． | where can I use QQ |
| C． | how I can use QQ | D． | whether can I use QQ |
Thousands of houses _______ by the floods in Guangxi last month.
| A． | destroy | B． | destroyed | C． | have destroyed | D． | were destroyed |
more, and you'll improve your spoken English.
| A． | Speak | B． | Speaks | C． | Speaking | D． | To speak |
. Wow.nice card!
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