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      There are four hats on the big table. They are red, yellow, green and white. They are Mike's, Bill's, Tom's

and John's. Tom's hat is not yellow, green, or red. John's hat is not green. And Mike's hat is not yellow or

green. What colour are their hats?

1. Mike's hat is _____________.

A. red

B. yellow

C. white

D. green

2. _____________ hat is green.

A. Mike's

B. Bill's

C. Tom's

D. John's

3. Is Tom's hat white or green?

A. Yes, it is.

B. No, it isn't.

C. It's white.

D. It's green.

4. Is the yellow hat John's or Tom's?

A. It's John's.

B. It's Tom's.

C. It's Mike's.

D. It's Bill's.

5. How many colours about their hats?

A. Two.

B. Three.

C. Four.

D. Five.

碱性糖制剂的组成与作用如何？