CHAPTER 15 / BEFORE CLASS / PREPARATION 01
Clean water, pure water
See why removing dirt is different from removing dissolved substances.
10–15 minutes · A guided first stepPrepare when your teacher assigns this topic; this is one core task, not the whole chapter. Answers save on this device. Download your record to share it with your teacher.
按老师指定的知识点完成，不必按章节统一赶进度。中文提示随时可用，不影响完成。当前进度保存在本机，可下载记录。
STEP 1 / 6
Get ready
You do not need to know these words yet. We will introduce them before asking you to use them.
如果还没学过，跟着模型和例题走即可。学过的同学可以先练习，不确定时回来看看。
By the end, you will be able to:
- Distinguish suspended solids from dissolved substances.
- Explain the roles of filtration and chlorination.
- Distinguish safe drinking water from chemically pure water.
This is preparation. You are allowed to be unsure; you do not need every answer right.
My work · 登录查看班级作业 ↗
For class tracking, open the assigned task from My work. / 需从“我的作业”打开老师布置的任务，再提交到班级。
Weekend preparation → weekday recall
These short cards help you recall the model and words before class. They are not another copy of this activity.
Download 3 recall cards · PDF ↓Browse all preparation tasks ↗