单项选择题
A.too low to
B.too high to
C.too high for
D.too low for
单项选择题 In restricted visibility a towed vessel must sound a fog signal when it is（）.
单项选择题 In reduced visibility，you hear two prolonged blasts of a whistle. This signal is sounded by a （）.
单项选择题 In order to maintain speed while changing course from a close reach to a broad reach，the sails should be（）.