有空

yǒu kòng zhī shí

有空之时

at leisure

nǐ yǒu kòng ma

你有空嘛？

Do you have any free time?

wǒ yǒu kòng jiù qù

我有空就去。

As soon as I have time I'll go.

xià xīng qī wǒ yǒu kòng

下星期我有空。

I'll be at liberty next week.