穿大绳时，需要（）人上井架操作。
A、1
B、2
C、3
D、4
参考答案：A
The doctor Robert carefully as soon as he was taken to the hospital.[ ]
A. look at
B. looked over
C. look after
D. looked for
酒精的热值是3.0×107J/kg，求完全燃烧200g酒精放出的热量？若这些热量全部被水吸收，可以把多少kg的水从40℃加热到沸腾？
