船舶强度大，马力大，稳性和浮性较好，但船体较小的船舶称为：（）

A condition where two currents meet at the downstream end of a middle bar can be determined by a（）.

What describes a flood current（）.

Throughout history, the language ______ by a powerful group spreads across a civilisation.

When a tornado moves over the water from land it is called a（）.

不符合“A”型船舶特点的其他船舶均称为“B”型船舶。

A公司与B公司签订《船舶转让协议》，约定A公司将船舶转让给B公司，转让价格为XX万元B公司交押金X万元，以后每月支付船价及利息X万元，如两个月内不付转让费，A公司有权收回船舶由B公司负责办理船舶营运手续B公司中途无故退回船舶，已付的转让费不再退回，等等。B公司经营船舶一年后，以A公司提供的船舶陈旧，操纵性能差等为由，向A公司提出终止船舶转让协议。A公司欲协商，但协商不成，A公司收回船舶国籍证书，船舶技术证书及营运证书。该协议属海商法范围内的何种合同？该协议是否有效

A．through B．across C．of D．on

Apparent wind speed blowing across a ship under tow can be measured by a(n)（）.

A current moving across a lock entrance toward the river or toward the dam is called a(n)（）.

Apparent wind speed blowing across a vessel under tow can be measured by a(n)（）.

As a ship moves through the water，it causes a wake，which is also moving forward relative to the sea. In addition to a fore and aft motion，this wake also has a(n)（）.