In 1620, about half the USA was covered by forests Today the forests have almost gone． A

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 country．The 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．
【小题1】In 1620, about      the USA was covered by forests．A．a thirdB．halfC．two thirdsD．a fourth【小题2】A lot of good land has gone with     ．A．sandB．waterC．windD．forests【小题3】The Great Green Wall in China is      long．A．7,000 kilometersB．1,700 kilometers C．7,000 metersD．400 kilometers【小题4】Trees must be grown in     .A．ChinaB．the USA C．some countriesD．every part of the world【小题5】     will make the world better．A．The Great WallB．Tall buildings C．Great Green WallsD．Flowers and grassB