Sure, here are the sentences with the subjects underlined and the verbs double underlined:

1. __Listening to music__ can be very __relaxing__
2. __They__ __bought__ a new car last week
3. __To travel during the holidays__ can be __expensive__
4. __What he wrote in the letter__ was __touching__
5. __The dog__ __barked__ at the stranger
6. __Drawing__ is a favorite hobby of many people
7. __To finish this project on time__ is __crucial__
8. __Her smile__ __brightens__ up the room
9. __Playing chess__ __requires__ a lot of patience
10. __To understand the problem__ we __need__ more information