Section C

16: [C] Only a few species cause troubles to humans.

17: [B] They can cause damages to people’s homes.

18: [A] Deny them access to any food.

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19: [D] The change in people’s immune system as they get older.

20: [B] Offer blood samples.

21: [C] Helping improve old people’s health conditions.

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22: [D] A group of kids were playing chess after school.

23: [C] Participate in national chess competition.

24: [A] Most of them come from low-income families.

25: [B] Think twice before taking actions.