Circle the correct item
1. Tina sunbathed/was sunbathing while her children swam/were swimming in the sea.
2. Mr White phoned/had phoned us after the conferense was beginning/had begun.
3. They are sailing/ had been sailing for two weers before they reacher the continent.
4.My brother bought/had bought this computer a year ago.
5.We had/were having breakfast when our neighbour knocked/had knocked at the door.
6.Tom's eyes were red because he had worked/had been working at the computer all day.
7.Dolly took/was taking a letter? opened/ was opening it and started/had started/had started reading.
8.After we cleaned/had cleaned the house we decided/had decided to go to the cinema.
9.The boys were playing/had been playing tennis at 3 o'clock yesterday.
10.Mrs David was upsed because she was losing/had lost her purs

а как это записать?

вам нужна ссылка на грамматическое правило? Если да, то я могу оформить

1 were swimming 2 phoned had begun 3 had been sailing 4 bought 5 were having knocked 6 had been working 7 took opened started 8 had cleaned decided 9 were playing 10  had lost8 cleaned / had cleaned оба правильные, я бы сказал cleaned т к последовательность понятна из-за after