三、单项（共5分, 每小题1分）
18. This kind of cake ______ sweet. I want one more.
A. seems B. tastes C. looks D. sounds
19. Read more English novels, ______ you will know a lot of English words.
A. and B. but C. so D. because
20. Betty has ______ cleaned her room but she hasn’t done her homework ______.
A. ever; yet B. just; already C. already; yet D. just; just
