19.　　 Child as he is, he knows how to live and study.

18.　　 However difficult the task may be, we will try/do our best to complete in time.

17.　　 Whatever you do, try your best.

16.　　 You will not succeed unless you work hard.

15.　　 It seemed only seconds before the boy finished washing his face.

14.　　 Hardly had I reached the airport when the plane took off.

13.　　 What a long way it is from Guangzhou to New York!

12.　　 What was the population in China by the end of last year?

11.　　 Try to express yourself in English. Don’t be afraid of making mistakes.

10.　　 Mother seldom goes out alone at night, does she?