船舶的推进器效率的通常值为：（）.
A.0.95～0.98
B.0.80～0.95
C.0.60～0.75
D.0.50～0.70
参考答案：C
He looked around and caught a man _______ his hand into a pocket of a passenger.[ ]
A. put
B. to be putting
C. to put
D. putting
四等水准测量中，黑面高差减红面高差±0.1m应不超过（）。
A.2mm
B.3mm
C.5mm
D.10mm
