我们五点下课，一起去吃饭吧。

Wǒmen wǔ diǎn xiàkè, yìqǐ qù chīfàn ba.

We finish class at five; let's go eat together.

我们三点下课。

Wǒmen sān diǎn xiàkè.

We finish class at three.

下课以后我们一起去吃饭吧。

Xiàkè yǐhòu wǒmen yìqǐ qù chīfàn ba.

After class, let's go eat together.