or else idiom
B2 否则，要不然
used to say what will happen if another thing does not happen
We must be there by six, or else we'll miss the beginning. 我们一定要在6点前赶到那里，要不然就会错过开场。
B2 （用于对比两种不同的事物或情形）要不，要么
used to compare two different things or situations
She's either really talkative and you can't shut her up or else she's silent. 她要么滔滔不绝，你都堵不上她的嘴，要么就一言不发。
informal（表示威胁，有时是一种幽默的说法）要不然，否则的话
used as a threat, sometimes humorously
He'd better find it quickly, or else (= or I will punish him in some way)! 他最好马上找到它，要不然，哼！