To reduce stress on the towing hawser when towing astern (ocean tow)，the hawser should be （）.
A. secured to the aftermost fitting on the towing vessel
B. just touching the water
C. underwater
D. as short as possible
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A free press is considered very important to the functioning of parliamentary democracy because（）.
A. it plays a watchdog function,keeping an eye on the government
B. it informs people of current affairs in the world.
C. it provides people with subjective reports.
D. it publishes short pamphlets for Parliament.
桩核冠的箍结构（ferrule）是指全冠边缘应该在牙本质一桩核界面以下至少（）
A. 2.5mm
B. 3mm
C. 不小于1mm
D. 3.5mm
E. 2mm
当6个砂浆抗渗时间有（）个表面出现渗水现象时应停止试验，记下当时水压。
护桩可采用钢轨或钢筋混凝土等材料；第一个护桩距最外股钢轨2.5～3米。（）
A. 正确
B. 错误
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