航海英語(yǔ)遇險(xiǎn)用語(yǔ)單項(xiàng)選擇題每日一練(2019.01.17)

來(lái)源：考試資料網(wǎng)

1 The color of rockets，shells，or rocket parachute flares used to indicate that the vessel is in distress and requires immediate assistance is（）.

2 All of the following are distress signals EXCEPT（）.

3 An orange flag showing a black circle and square is a（）.

4 The service life of distress signals must be not more than（）.

5 What is NOT a distress signal?（）