they didn't have to be afraid of catching SARS如何对CATCHING SARSthey didn't have to be afraid of catching SARS如何对CATCHING SARS提问
问题描述：
they didn't have to be afraid of catching SARS如何对CATCHING SARS
they didn't have to be afraid of catching SARS如何对CATCHING SARS提问
答
What didn't they have to be afraid of?
答
catch 表示染上某种疾病.如catch cold 感冒
What didn't they have to be afraid of?
答
catching 是易传染的意思,这里catching SARS是动名词短语作介词of后面的表语
答
他们没有必要去害怕感染非典病毒