1. be bad at 不善于。如:
I’m bad at maths. 我数学学得很差。
He is bad at playing tennis. 他网球打得不好。
2. be bad for 对……不好。如:
Too much salt can be bad for you. 吃太多的盐对你不好。
Smoking is bad for you (your health). 抽烟对你(你的身体)有害。
3. go from bad to worse 变得越来越糟,每况愈下。如:
His business is going from bad to worse. 他的生意每况愈下。
We’re hoping for an improvement but things have gone from bad to worse. 我们希望有所改善,但情况却变得越来越糟。