阅读理解。 What do you do if you're stranded

问题：

阅读理解。

     What do you do if you're stranded (处于困境的) on a lonely island? Surely you need to find a way to

get in touch with the outside world. Your best chance of doing this is to draw the attention of a passing plane. 　　

     Body signals (信号) 　　

     Pilots from different countries understand body signals if they have the correct training. When you wave

your arms up and down in a straight line, it means "yes". When you point downwards and swing your arm

from side to side, it means "no". If you want the pilot to know that it's safe to land, push your hands out in

front of you and bend (弯曲) your knees. If you want to say that it's not safe to land, put your arms in the

air and move them to one side. 　　

     Smoke signals 　　

     The smoke from a fire can be seen from far away, so it's a good way to draw attention. If the weather

is dry, it isn't hard to start a fire. Remember, however, that fires can be very dangerous if they get out of

control. Never light a fire unless you're sure that it can't spread. If the ground is dark, light smoke can be

seen more easily. Green grass and leaves produce light smoke. 　　

      Ground-to-air signals 　　

       It's a good idea to build some signals, too. Use large pieces of wood to make the symbols (标记). If

you can't find any wood, use earth. Some useful symbols are: 　　

      F"I need food and water." 　　

      II"I need medicine." 　

   　I"I am badly hurt." 　　

     X" I am unable to move from here." 　　

     Pilots' replies 　　

     If the pilot lowers the plane's wings from side to side, this means "message received and understood".

(At night, the pilot flashes the plane's green lights.)

     If the pilots flies the plane in a clockwise circle, this means "message received but not understood".

(At night, the pilot flashes the plane's red lights.) However, there is no signal which means "message not

received". Why not?

1. Which picture means "it's not safe to land"?

2. What can we learn from the passage? 　　

A. Swinging your arm from side to side means "yes". 　　

B. If the ground is dark, light smoke can't be seen. 　　

C. If you need some medicine, make a symbol "II". 　　

D. The pilots make replies with a blue light at night.

3. What is the passage mainly about? 　　

A. The explanation of building signals on an island. 　　

B. The importance of making signals on an island. 　　

C. Ways of sending out signals on a lonely island. 　　

D. Ways of receiving signals from a lonely island.