for certain

Magical properties are sometimes claimed for certain medicines.

某药物被认为有时具有神奇的效应。

Not obtrusive, go up pertly courtship, you can refuse for certain.

撞，冒冒失失上去求爱，你肯定会遭拒绝。

Miners are a high risk group for certain types of gastric cancer.

矿工是极易患某几种胃癌的高风险人群。

I don't know for certain.

我并确切知道。

Some negative effects may be caused during postwelding heat treatment of certain component and steel for stress-relief.

特别指出对某钢材或构件进行热处理，在消除应力的同时，也可能带来一的作用。