Cách dùng in , on, at

1. We go swimming (a)   summer.

1. My birthday is (a)   Sunday.

1. I get up (a)   6 o'clock.

1. She visits her grandparents (a)   the weekend.

1. They play volleyball (a)   the beach.

1. School starts (a)   September.

1. We watch fireworks (a)   New Year's Eve.

1. Birds sing (a)   the morning.

1. I do homework (a)   the afternoon.

1. He sleeps (a)   night.