21. the Great Green Wall will stopthe wend from blowing the earth away.
22.Ayoung man practiced speaking English with Mr Green.
23.His train ride seemed short, but his memory of the trip will last long.
24. It was a long trep, but none of them felt tired.
25.Stand here, and Iwill pass you some lights.
26. How about Hainan Island?/What about tomorrow?
27. It is a pretty city with an interesting flower market.
28. It takes about twelve hours to go there if you take the K37 train.
29.They spend the day playing with the new toys.
30.How much does a car cost in China?