1 . 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）

2 . 如果伤口继续暴露在外面，它就会感染的。(根据汉语提示完成句子)
If the wound remained ____________, it will get ____________.

3 . Most people who’ve had chicken pox(水痘)once are _____it for the rest of their lives.

A．free from

B．immune to

C．concerned about

D．infected with

4 . Washing hands thoroughly is one of the effective ways to avoid ________ by virus.

A．being infected	B．infecting
C．to be infected	D．to infect