22Questions 22 to 25 are based on the passage you have just heard
A. .A)His students had trouble getting on with each other.
B)A lot of kids stayed at school to do their homework.
C)His students were struggling to follow his lessons.
D)A group of kids were playing chess after school.
23
A)Visit a chess team in Nashville.
B)Join the school's chess team.
C)Participate in a national chess competition.
D)Receive training for a chess competition.
24
A)Most of them come from low-income families.
B)Many have become national chess champions.
C) A couple of them have got involved in crimes.
D)Many became chess coaches after graduation.
25
A)Actions speak louder than words.
B)Think twice before taking action.
C)Translate their words into action.
D)Take action before it gets too late.
免疫的概念是
A. 机体的抗微生物感染功能
B. 机体清除损伤和衰老细胞的功能
C. 机体排除非自身物质的功能
D. 机体识别、杀灭与清除外来微生物的功能
E. 机体识别和排除抗原性异物的功能
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