The policeman asked the child ________ cross the street ________ the traffic lights turned green.

You look tired， Miss Green.–yeah . Icomputergames for two hours.

Scissors can be dangerous, so you ____________ play with them.— OK, I won’t.

This is _____ dictionary I bought you in Beijing. I think it’s _____useful one for you.— Thank you, Mum.

People have planted a great many trees in order to ____wind and sand in the desert.