change the active voice into the passive voice.主动改被动Do they take care of the sick?He was operating on an old patient.I will be looking into the matter.You may find this kind of trees everywhere.

(1)"Is" the sick taken care of ?
(2)An old patient "was being operated on "
(3)The matter "will be looked into "
(4)This kind of trees "may be found" everywhere.
注:被动语态的使用目的主要有以下三点:
(1)谁做的动作不知道
(2)说出谁做的没必要；
(3)动作承受者需强调
所以上述句子在变被动句时我都没有再加上主语,如果还想表明谓语动作的施动者是谁,那就在句尾加上"by + 动作施动者"
补充:(1)中我用了"is"没用"are"是从"sick"本身就可作名词"病人"讲考虑的,如果把"sick"看成是形容词,那么"the sick"就是指"病人"这一类人.前面用复数"are"
(3)中如果谓语时态是将来进行时或完成进行时，变被动语态改为将来或完成时一般式被动句即可.
祝 学习进步!

Does the sick be taken care of by them ? An old patient was operated on by him . The matter will be looked into by me . This kind of trees may be found everywhere .

Are the sick been taken care of?The old patient is being operated on by him.The matter will be taken good care of.(the matter will be looked into)This kind of trees can be found everywhere.

Are the sick taken care of by them?
An old patient was being operated on by him.
The matter will be looked into by me.
This kind of trees may be found everywhere by you.