12.第二单元
13.I'm sorry to hear that your sister is ill.
14.i hope you will come well soon
15.it is important to study chinese well
16.they are talking about this
17.we should do exercise for keep fit
18.it is important for us to keep realising
19.what's wrong with you?
20.you ought do exersise to keep healthy
21.it is impoertant to have a 8-houer sleeping every nigt
22.there is so crowded on weekdays