It's red lights．We must ________．

A．stop

B．wait

C．go

It’s time ________ say goodbye．

A．to

B．in

C．on

It’s eight ________．Time to go to school．

A．clock

B．o’clock

C．o’clock

It’s hot today, ________?

A．is it

B．it isn’t

C．isn’t it

It’s nine o’clock．It’s late ________ class．

A．to

B．in

C．for