Here are the sentences filled in with the correct forms of the verbs:

1. She **goes** to the museum every month.
2. Peter **plays** soccer on weekends.
3. They **think** that it’s a good idea.
4. He usually **eats** breakfast at 7 AM.
5. The train **arrives** at 6 PM.
6. We **study** English in the evenings.

### Explanation:
- The present simple tense is used in these sentences because they describe habitual actions or routines.
- The verb forms change depending on the subject (e.g., "go" becomes "goes" with "she" and "play" becomes "plays" with "Peter").