He is living in a world of ignorance.

Yumi is my best friend.

He made an error in that calculation.

Last week, I went to see a movie with my friends.

His room is shabby.

Since my grandmother's health has been deteriorating, I decided to take care of her.

He has changed so much that he is a mere shadow of his former self.

We started a collaboration for a new project.

We decided to collaborate on a new project.

Have you ever seen a horse cribbing?