环保话题写作 — 英语填空题
题目
补全短文。用下面的词组成一个句子，填在横线上，每个词限用一次。We want to protect the Earth. We can save water and use less plastic. ___ Then we can use less energy, too.
词语：leave / room, / a / lights / the / off / turn / should / we / When / to / save / energy.