Unit 2 What is happiness to you?
第二层级——背句子、学衔接，让作文字顺意畅
1．Too many trees have been cut down.
许多树已被砍倒。
2．It has caused birds and animals to lose their natural habitats.
这让鸟类和动物失去了它们的自然栖息地。
3．Rubbish and waste water are being poured into the river.
大量的垃圾和废水正涌入河流。
4．Water sources have become badly polluted.
水资源已被严重污染。
5．We must take action to protect the earth now.
