The swing door was opening and closing in the wind.

He is playing outside.

In addition to keys and wallets, there are many small items in my bag to take outside.

He is playing outside the house.

He is deeply interested in Buddhist teachings, but he is open to learning non-Buddhist teachings as well.

He is playing outside.

He peeped through the door scope to see who had come.

The swing door of this restaurant opens and closes automatically.

He went to the hospital to have his urine tested.

A back vowel is a vowel that is pronounced at the back of the mouth.