You had better beware.

那你最好要小心。

youdao

But they had better beware: using text messages to flirt with the unwilling can result in a fine.

但他们最好小心了，如果把短信发给无意与自己调情的人，可能会招致罚款。

youdao

Dry eyes, dry mouth, nose stem...... When you feel that they seem to have skin glands in the "dry" state, you had better beware incoming Sjogren's syndrome.

眼干、口干、鼻干……当你感觉自己全身皮肤腺体似乎都处于“干涸”状态时，可要当心干燥综合征来袭。

youdao

Anyone caught selling a gallon of unleaded at an unseemly rate had better beware (and maybe hire some lawyers).

FORBES: Obama's Oil-Price Schizophrenia

Entrepreneurs and executives had better beware.

FORBES: Magazine Article

Your bank will likely give you a better rate, but beware transfer costs and commission fees.

BBC: How to budget for living abroad