Mary often helped her mother ________ out the trash last year.

What did Mr Wu tell you to do, Jim?—He told me to go home early and _____ in the street.

Trees on the hills can stop the rains from away the soil.

There will be ________water and ________trees in 100 years, how can we live?

I’m a little weak in Maths. I don’t know how to improve it. — Why not __________ Daniel for help? He’s very good at it.