, Нужно объяснить почему это время мы выбрали для предложений... И вставить в пропуски

1) Sheila has done to the bazaar. She'll be back in an hour.

2) You look sweaty! Have you been working out?

3) How much has Helen spend on her English books?

4) The house smells wonderful! Has Mum baked a cake?

5) How long has Tom been saving to buy a new PC?

6) Robin has never been abroad.

7) He has worked very hard recently. He needs some time off.

8) We haven't bought all our Christmas presents yet.

9) Joy has been cleaning the house since 9 o'clock. Can you give her a hand?

10) Have you ever eaten Thai food?