水位计安装在竖井的测站要检查（）。
A、开关的工作状态
B、平衡球的运行情况
C、进水管的淤塞情况
D、固态记录工作状态
参考答案：C
All the books written by Dickens are available in our library. You may borrow ___ you love. [ ]
A. whatever
B. whichever
C. whenever
D. however
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