交际运用。根据对话内容，在空白处填写适当的话语（话语可能是一个句子，也可能是一个短 语或一个词），使对话完整。 A: It's spring now.  The wind is blowing strongly.  We can see plastic bags everywhere. 1 bad the environment is! B: Yes, as a citizen, it's important to take care of the environment. 2 ? A: We'd better not use plastic bags. We should 3 to school if necessary. Riding a bicycle can keep us healthy, too. B: At the same time, we shouldn't 4 . It's our duty to keep our environment clean.  And turn off the lights if possible. A: 5 .  If we try our best to protect our environment, it will get better and better. B: Yes.  Let's work together to protect our environment.