本单元的重点句子包括：
1. What do you usually do on weekends? (你周末通常做什么？)
2. I usually play basketball with my friends. (我通常和我的朋友们打篮球。)
3. What are you doing now? (你现在在做什么？)
4. I am reading a book. (我正在看书。)
5. What did you do last weekend? (你上个周末做了什么？)
6. I went to the park with my family. (我和我的家人去了公园。)
7. How often do you exercise? (你多久锻炼一次？)
8. I exercise three times a week. (我每周锻炼三次。)
这些句子主要涉及到日常生活中的活动和习惯，以及过去和现在的事情。学生们应该学会用英语描述自己的活动和时间，并能够简单地交流关于日常生活的话题。同时，学生们也需要掌握一些常用的时间状语和频率副词，比如usually、often、sometimes、once a week等等。通过这些句子的学习和练习，学生们可以进一步提高自己的口语表达能力，并且更好地理解和运用英语语言。

可能包括：
1. What's wrong with you?
2. I have a toothache.
3. Do you need to see a dentist?
4. Let me help you.
5. Where is the hospital?
6. Don't eat too much candy.
7. It's good for your teeth.
8. You should floss your teeth.
9. You should take this medicine.
10. You should rest and drink plenty of water.