二、阅读判断
16. Viruses can only live inside people or animals.
答案：B
17. All bacteria cause illnesses.
答案：B
18. Washing your skin can prevent some illnesses.
答案：A
19. Germs can enter the body through the eyes.
答案：A
20. The heart contains the bodys strongest muscle.
答案：C
21. After they kill germs, antibodies stay in the body.
a
答案：A
22. Vaccines can make you sick.
答案：B