单项选择题
A.stop your engines B.sound two prolonged blasts of the whistle C.sound the danger signal D.slow to bare steerageway
A.Dead in the water B.1 knot C.10 knots D.15 knots
A.Starting with a dash and extending radially outward from the target B.As a broken line from center of PPI to the target C.Starting with a dot and extending radially inward from the target D.Starting with a dash and extending to the right of the target