18．Dear Jack，
How are you？I have been in the USA for six months．I like the life here．I have a few friends．I don't have much homework．There are a lot of sports at my school，but I don't like sports at all．I like the food very much．I eat a lot of different kinds of food every day．I like coke（可樂）very much．I don't drink water． I drink coke instead（代替）．I'm enjoying my life here．The sad thing is that sometimes I get ill． I don't know why．My parents say I must go on a diet and do more sports．Must I？
Yours，
David
任務(wù)一：根據(jù)短文內(nèi)容回答問題．
66．Who writes this letter？
David．
67．Does the writer know why he sometimes gets ill？
No，he doesn't．
任務(wù)二：按要求完成下列各題．
68．I like coke（可樂）very much．I don't drink water．（改成并列句）
I like coke very muchso I don't drink water．．
69．The sad thing is that sometimes I get ill．（改為一般過去時(shí)）
The sad thingwas that sometimes Igot ill．
70．文中句末的"Must I？"是省略句，請把句子補(bǔ)充完整．
Must Igo on a diet and do more sports．？
