Here are the suggested answers for the blanks in the exercise:

1. **see** her very often.
2. Most rivers **flow** into the sea.
3. She **washes** clothes twice a week.
4. He **becomes** (be) a teacher of English. He **doesn't** (not) like.
5. She never **does** anything that she **doesn't** (not) like.
6. They **do not have** (not have) a bicycle, so they **walk** to school every day.
7. She **studies** hard every day. She **wants** to be a doctor in the future.

### For the negative sentences:
1. He is **not** the best in the class.
2. Peter **does not** do homework in the evening.
3. We **do not** play football after school.
4. You do **not** run fast.
5. Tim and Lucas **do not** work at weekends.
6. I do **not** like classical music.
7. These exercises are **not** difficult.
8. She does **not** have science on Fridays.

### For the questions in the present simple:
1. **Do you have** an art lesson on Monday? (No) **I do not.**
2. **Do they ride** their bikes to school? (Yes) **They do.**

Feel free to ask if you have any more questions!