大家在备考英语四六级考试时一定要多做真题，这样才能更好地把握题目难度和重点词汇等等。今天小编为大家带来2019年12月英语四级听力真题试卷一：听力篇章2（沪江网校），希望对你有所帮助~

Questions 19 to 21 are based on the passage you have just heard.
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.

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

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

参考答案：19. D 20. B 21. C 

以上就是今天为大家分享的内容啦，各位小伙伴利用好最后的时间认真备考。小编祝大家旗开得胜！