In 1620, about half the USA was covered by forests. Today the forests have almost gone. A lot of good land has gone with them, leaving only sand. China doesn't want to copy the USA's example. We're planting more and more trees. We've built the " Great Green Wall" of trees across northern part of our Great Green Wall is 7,000 kilometres long, and between 400 and 1,700 kilometres wide. It will stop the wind from blowing the earth away. It will stop the sand from moving towards the rich farmland in the south. More "Great Green Walls" are needed. Trees must be grown all over the world. Great Green Walls will make the world better.
根據短文內容，選擇正確答案。
1620, about ______ the USA was covered by forests.
A.a third thirds D.a fourth
2.A lot of good land has gone with ______.
r sts
Great Green Wall in China is ______ long.
A.7,000 kilometers B.1,700 kilometers
C.7,000 meters D.400 kilometers
s must be grown in ______.
a USA countries y part of the world
5.______ will make the world better.
Great Wall buildings
t Green Walls ers and grass
KEY: 1.B 2.D 3.A 4.D 5.C
