用方框中所给单词的适当形式填空，使短文通顺正确、连贯（每个单词限用一次）。

This month’s goal for helping to save our planet!

Week1: This week,my family tried to save electricity.We never left the lights _小题1:___ when leaving the rooms.We switched off the TV when __小题2:___was watching it.Mum only used cold water in the washing machine.

Week2: We started recycling this week.We tried to write on ___小题3:__ sides of our paper,not just on one side.We also divided our rubbish into ___小题4:__bags for bottles,cans,paper and food.Plastic bags from the supermarket were ___小题5:___so we can use them again as rubbish bags.

Week3: We stopped taking long baths and had short showers ___小题6:___.We flushed the toilet with __小题7:___ water.When mum and dad made tea or coffee,they used less water in the kettle(水壶).My sister and I didn’t leave the tap running when we brushed our ___小题8:__.

Week4: Mum used to __小题9:___ us to school,but now my sister and I have started riding bikes to school.This week dad and a few of his workmates started to go to work together in one car and share the cost.My fridends and I became volunteers at school.We are taking the __小题10:____step to help make our school more earth-friendly.

衡摩尔流假设指什么？其成立的主要条件是什么？