A. 1950

B. 1996

C. 1n the ninety century sixty years

D. in the twenty century fifty years

④ What is the meaning of diversity in a group ?

A. It means passing on the ability to resist that disease to their children

B. It means having animals with their genes arranged in different ways

C. It means all of them would be left to continue the species if there is a new illness

D. It means all of them might die of the same illness

Suggested Answers:

① C ② D ③ D ④ B

(2) Ask Ss to read the text again and have a discussion according to the requirement of Ex2 on P16. Ss work in groups; when discussing, the head of each group should write down the opinions of all the members. Ask some volunteers to show their opinions.