超星 - 6-2-2段落听力2

单选题

[音频]【单选题】Question 19 to 21 are based on the passage you have just heard. Question 19:

A. The function of the human immune system.
B. The cause of various auto-immune diseases.
C. The viruses that may infect the human immune system.
D. The change in people’s immune system as they get older.

查看答案

单选题

【单选题】Question 20:

A. Report their illnesses.
B. Offer blood samples.
C. Act as research assistants.
D. Help to interview patients.

查看答案

单选题

【单选题】Question 21:

A. Strengthening people’s immunity to infection.
Better understanding patients’ immune system.
C. Helping improve old people’s health conditions.
D. Further reducing old patients’ medical expenses.

查看答案