Вопрос по английскому языку:

Помогите пожалуйста.
Correct mistakes where necessary in the use and formation on the Possessive Case.
1. You can buy all this medicine at the chemist.

2. Childrens voices could be heard far away.

3. First we had lunch at Bill and then went to the cinema.

4. There's no doubt you know quite a lot about our country
history.

5. A woman voice behind me pronounced my name several
times.

6. We decided to meet in two week’s time.