问题补充:
As you know, it is our duty to my younger sisters from being hurt when they are in trouble.
A. prevent
B. save
C. stop
D. protect
答案:
A. prevent
B. save
C. stop
(答案→)D. protect
解析:句意:如你所知,当我们的妹妹处于困境中时保护她们不受伤害是我们的职责。it is our duty to do,it是形式主语,to do sth是真正的主语;save节省,挽救; prevent…from…/ stop…from…阻止某人做某事;protect…from…保护某人/某物不受伤害。这里hurt的逻辑主语是my younger sisters,它们之间是被动关系,故这里用的是being hurt它是动名词的被动语态。根据句意故选D。