Prepositions of time:in, on, at

My birthday is __ April

Children play snowballs __ winter.

People give each other presents __ Christmas.

Bill cleans his teeth __ the morning.

I got many presents __ my birthday.

She usually gets up __ 7 o'clock.

We celebrate Easter __ spring.

Tom has got Art __ Monday.

I went to my grandparents __ holidays.

Jane always visits her relatives __ Christmas days.

Kate doesn't go to school __ weekend.

I often help my mother __ the afternoon.