When vs While

I was walking to school ______ I saw a strange animal.

• while

• when

______ she was cooking dinner, the phone rang.

• when

• while

He was reading a book ______ his friend knocked on the door.

• when

• while

______ we were watching TV, the electricity went out.

• while

• when

______ I was studying, my friend called me.

• when

• while

She was painting the house ______ it started to rain.

• when

• while

______ he was driving home, he heard a loud noise.

• when

• while

______ I was jogging in the park, it started to rain.

• when

• while

______ she was reading a novel, her cat jumped on her lap.

• while

• when

They were having dinner ______ the lights went out.

• while

• when