Smoking is a bad habit.

吸烟是一种坏习惯。

It's hard to break a bad habit.

改掉坏习惯很难。

Biting your nails is a bad habit.

咬指甲是个坏习惯。

It takes time to break a bad habit.

改掉坏习惯需要时间。

He has a bad habit of spit everywhere.

他有随地吐痰的坏习惯。

He has a bad habit of biting his nails.

他有一个恶习，总是咬指甲。

He is always late, which is a bad habit.

他总是迟到，这真是个坏习惯。

Smoking is a bad habit that is hard to quit.

吸烟是一种难以戒掉的恶习。

You should not suk on your pen; it's a bad habit.

你不应该吸吮你的笔；这是个坏习惯。

Lying is a bad habit.

说谎是一个坏习惯。