There is a mistake in the underlined parts in the following sentences, find and correct it: I still think children can did a lot of things

1. I buyed a different for my friend in America last year
2. My parents take me to a zoo in North America on a fine Sunday.
3. My parents are always think that I am not old enough to do what I wanted,
4. I still think children can did a lot of things.
5. We work very hardly but we have fun working together