拖轮以垂直方向拖大船船首时，大船将绕其（）转动。
A.船首最前端
B.船舶重心处
C.船舶转心处
D.船尾最后端
参考答案：C
-Bill Gates was so nice that he decided to ninety percent of his money to charities.
A．give up
B．give away
C．give out
D．give off
