单项选择题
A vessel conducting mine clearing operations will show（）.
A.three balls in a vertical line B.two balls in a vertical line C.one ball near the foremast and one ball at each fore yard D.one diamond near the foremast head and one ball at each fore yard
单项选择题 A vessel being towed will show（）.
单项选择题 A vessel being towed astern shall show at night（）.
单项选择题 A vessel being pushed ahead is required to carry which of the following lights?（）.
