Look at the diagram below．It shows a cross-secrio （橫截面）of a mountain and the land on each side of it．The sea is on the west side of the mountain．

In January，F(xiàn)ebruary and March，warm wet winds blow strongly across the sea towards the mountain．The winds pick up moisture（濕氣）as they blow across the sea．When clouds reach the mountain，they rose and become cooler．The higher they have to go，the cooler they become．The moisture in the clouds turns to rain．As a result，the clouds drop rain on the west side of the mountain，which sometimes has problems of flooding．Some of the clouds pass over the mountain but there is little rain in them．

In July and August，winds blow from east towards the mountain．They pass over the wide land．where it is usually very dry．The winds become hot and dry．They rise when they meet the mountain．They do not form（形成）clouds because there is little moisture in the hot dry air．

The diagram shows why（in many countries）there are better farms on one side of a mountain but there is a desert on the other side．

1．Suppose it is in the northern part of the earth，which season is dry?

A．Spring．              B．Summer               C．Autumn．               D．Winter．

2．Which Part in the diagram is good for farming?

A．From Point A to B．                                B．From Point C to D．

C．From Point D to E．                                   D．From Paint E to F．

3．What is the most important cause of the rain?

A．The sea．            B．The winds．        C．The mountain．      D．The desert．

4．Why don't the winds from Point G form clouds?

A．Because the winds are not strong enough．

B．Because the winds don't pass over the desert．

C．Because there is little moisture in the air．

D．Because the winds don't reach the mountain．