21. 广州是中国第三大城市。
Guangzhou is city in China.
20.Don’t stop. Continue (read).
19.Tom has some (difficult) with his homework.
18.The sun shines. It’s (sun) today.
17.The (leaf) fall down from the trees in autumn.
16.December is the (twelve) month of the year.
9.be based on 10.put out
7.as soon as possible 8.be known as
5.去……的路上 6.rather than
3.注意 4.根据