把 or 被

把 and 被 both put the object before the verb, but from opposite sides.

• 把: the doer is the subject. Doer + 把 + object + verb + result. 请把门关上 (please close the door), 我把作业写完了 (I've finished my homework).
• 被: the thing affected is the subject. Thing + 被 (+ doer) + verb + result. 我的自行车被偷了 (my bike was stolen), 手机被弟弟弄坏了 (my phone was broken by my brother). The doer can be left out.

In both patterns the verb doesn't stand alone: it needs a result (完, 好, 坏), a place (放在桌子上), a direction (走) or at least 了. 被 usually reports something unpleasant or unexpected. In everyday speech 让, 叫 and 给 can replace 被, but 让 and 叫 need a doer after them. The formal 将 can replace 把.