我们今天晚饭吃了菠菜、土豆、番茄和葱。

Wǒmen jīntiān wǎnfàn chī le bōcài, tǔdòu, fānqié hé cōng.

We had spinach, potatoes, tomatoes, and scallions for dinner today.

我晚上吃了土豆。

Wǒ wǎnshang chī le tǔdòu.

I ate potatoes for dinner.

我喜欢吃土豆。

Wǒ xǐhuān chī tǔdòu.

I like eating potatoes.