单项选择题
When we hoist national flag together with other flags, we should keep the national flag in the （）place.
A.centre B.lower C.A+B D.A o rB
单项选择题 We can’t hoist （）national flag.
单项选择题 The sailors should show the relevant （）by day.
单项选择题 You should （）the mooring lines according to the changes of draft.
