Doctors and nurses tended the injured. 医生和护士护理受伤者。 

Ambulance crews were tending to the injured. 救护车上的救护人员在照料受伤者。 

tend作护理，照料时，用作及物动词和不及物动词，究竟有什么区别呢？例如以上2句，可以互换使用吗？

     【答】二者意义相同。区别：tend to sb 过去经常使用，但现在听起来已经过时。

       tend /tend/ v. ... 2. also 又作 tend to sb/sth [T] old-fashioned to look after someone or something  【过时】照顾，照料：Sofia was in the bedroom tending to her son. 索菲娅在卧室照料她的儿子。（摘自《朗文高级英语应试词典》p.2455）

      He tended his ailing mother. 他照顾生病的母亲。（摘自《韦氏高阶英汉双解词典》p.2164）

      The nurse tended to their wounds. 护士护理了他们的伤口。（同上）