1. We know him and  his friends.
2. The coat was soft and  warm.
3. It is stupid to do that so it is quite unnecessary.
4. I wanted to go but  He wanted to stay.
5. You can go there by bus or  by train

1 .We know him. We know his friends.
We know him and his friends.
2 . The coat was soft. The coat was warm.
The coat was both soft and warm.
3 . It is stupid to do that. It is quite unnecessary.
It is quite unnecessary and stupid to do that
4 . I wanted to go. He wanted to stay.
I wanted to go but he wanted to stay.
5. You can go there by bus. You can go there by train.
 You can go there by bus or you can go there by train.