你有一双大眼睛。

Nǐ yǒu yì shuāng dà yǎnjing.

You have a pair of big eyes.

你喜欢单眼皮的还是双眼皮的？

Nǐ xǐhuān dānyǎnpí de háishi shuāngyǎnpí de?

Do you like single-eyelid or double-eyelid (girls)?

我买了一双新鞋子。

Wǒ mǎi le yì shuāng xīn xiézi.

I bought a new pair of shoes.