1)When I was on the Black Sea last summer I swam in the sea everyday.When we came to the beach our friends were already swimming in the sea.
2) Yesterday when I was listening to the radio my brother phoned me. Yesterday I listened to the 10 o'clok news on the radio and went to bed.
3) I was going to the office yesterday morning when I met Mr.S. Yesterday I came to the office at a quarter to 9. The secretary brought me the mail and I went through it.
4) At a quarter to 9 yesterday my son was having breakfast.