Some exchange students         with their host families this time yesterday.

—Mr. Lee        to a student when I entered the classroom this morning.
—He is very patient        he is young.

My mother         the dishes when I got home.

Bob took a photo of his girlfriend while she           at the party.

—You were not in when I went to you yesterday.
—Oh, I         for a friend from England at the airport at that moment.

Millie         a picture when Mr.Green came in.