Помогите найти ошибки в предложениях, please

1)Don't forget to buy (Я думаю any, вместо A) a tea
2)At five o'clock English people have the tea with sandwiches and cakes.

3)Cows give us ( думаю, артикль надо заменить на any или some) the milk and meat.

4)He often says me that he is very busy.