被动语态的主语是接受动作。侧重说明主语接受动作，无须或者无法知道动作的执行者是谁。比如：Letters are collected from this mail box at7:30 a.m.上午7:30从这个信箱收取信件。
情态动词的被动语态
情、助、有、是妥安排，一律随新主语变。
带情态动词和助动词等的被动态如何处理比较复杂。要随新的主语来变化，这些词如“can, could; will, would; shall, should; may, might; must; ought to; need（需要）;have to（不得不）;be going to; to be to; used to; seem to; happen to等。例如：
主动：We must keep this inmind.
被动：This must be kept inmind.
我们必须把这个记在心里。
主动：We can put the refrigerator in that place.
被动：The refrigerator can be put in that place.
我们可以把电冰箱放在那个地方。
主动：We shall not use the washing machine again.
被动：The washing machine will not be used again.
我们不能再用那台洗衣机了。 原来的谓语“shall use”被动态中随新主语变为“will”。
主动：We shall take more measures to prevent corrosion.
被动：More measures will be taken to prevent corrosion. （“shall”变“will”）
我们将采取更多的措施来防止腐蚀。
I ought to be criticized for it. 我应该为此受到批评。
All this has to be solved with great care. 这一切得认真解决。
The lobby is going to be rebuilt. 门厅将被重建。
The exhibition is to be opened tomorrow. 展览会将在明日开放。
