1 . As many as ten million children ________ (infect) with the virus by the end of the decade. (所给词的适当形式填空）

2 . So what happens when a computer gets infected __________ a virus? (用适当的词填空)

3 . It is not possible to ________(infection) another person through kissing. (所给词的适当形式填空）

4 . Eggs known to __________ (infect) with salmonella (沙门氏菌) were allowed to go on sale. (所给词的适当形式填空）

5 . A good teacher should be able __________ (infect) his students with his own keenness for his subject. （用所给单词适当形式填空）