玻璃管液位计要定期对玻璃管内部进行（），保证玻璃管的清洁，防止玻璃管被损坏
A、清洗
B、更换
C、检修
D、重新刻度
参考答案：A
长江:青海
A．珠江：云南 B．海南：海河C．黄河：西藏 D．新疆：辽河
"Will you be able to finish the job this week?" " ___ ."
A．I can't say it
B．I don't know that
C．I'm not sure this
D．I don't expect so
