6. 同学们已经从方方面面对环保问题进行了了解。读一读，用所给单词的适当形式填空。
① We must (keep) our city clean.
② People can use an empty bottle (make) a vase.
③ There (be) a lot of cans in the rubbish bin.
④ A week ago, a woman (buy) some water at the supermarket.
⑤ The cleaner (find) many plastic bottles and put them into a truck.

① keep
② to make
③ are
④ bought
⑤ found

① 句意要求用所给动词适当形式填空，"must"后接动词原形，故填"keep"。
② "use sth to do sth"为固定搭配，表示用某物做某事，故填"to make"。
③ "a lot of cans"为复数，且为一般现在时，故填"are"。
④ "a week ago"为一般过去时标志，动词用过去式，"buy"的过去式为"bought"。
⑤ 句意描述过去动作，"find"的过去式为"found"。

7. 这是做文明市民倡议书的一部分。读一读，根据图片提示，完成下列句子。
①②③④⑤
① To make our city a better place, we should .
② To make our city a better place, we should .
③ To make our city a better place, we must .
④ To make our city a better place, we shouldn't in public places.
⑤ To make our city a better place, we should .

由于您未提供图片提示，无法准确完成句子填空。请您补充图片信息，以便我为您解答。

三、拓展性作业
1. 和你的小伙伴一问一答，想想如何进行旧物再利用。
|Things|How to reuse it?|
|----|----|
|a small can|Put rubbers and crayons in it, and it'll be a pen holder.|
|old clothes|make a handbag|
|newspaper| |
|plastic bags| |
|second-hand water| |
S1: How do you reuse...?
S2: I can... Then it'll be...

|Things|How to reuse it?|
|----|----|
|a small can|Put rubbers and crayons in it, and it'll be a pen holder.|
|old clothes|make a handbag|
|newspaper|Wrap things with it, and it'll be packaging materials.|
|plastic bags|Use it again when going shopping, and it'll be a shopping bag.|
|second-hand water|Water the flowers with it, and it'll be water for plants.|
S1: How do you reuse newspaper?
S2: I can wrap things with it. Then it'll be packaging materials.
S1: How do you reuse plastic bags?
S2: I can use it again when going shopping. Then it'll be a shopping bag.
S1: How do you reuse second - hand water?
S2: I can water the flowers with it. Then it'll be water for plants.