Passive for bad things: bị + (doer) + verb

When something bad is done to someone, put bị before the verb: Anh ấy bị phạt. He got fined. To say who did it, put the doer straight after bị, with no word for "by": Em bị chó cắn. I got bitten by a dog. Hôm nay em bị sếp la. My boss told me off today (in Hà Nội, mắng).

Bị tells the listener that the speaker sees it as bad news. For good news, the same pattern uses được: Em được sếp khen. My boss praised me. So the choice between the two is about feeling, not grammar.

Unlike an English passive, the person who suffers can come first when something of theirs is affected, and the thing goes after the verb: Em bị mất bóp. I've lost my wallet, or it's been stolen (in Hà Nội, ví). Chị bị giật điện thoại. Someone snatched my phone.

Time words go before bị: Hôm qua anh bị phạt.

Before an illness or a broken machine, bị has no doer and no action: bị cảm, bị hư. That's a neighbouring pattern.