Simple directional complement: V + 来 / 去
补语 / complements (趋向补语)
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
Verb + 来 / 去 / Verb + Place + 来 / 去
来 and 去 after a movement verb show the direction relative to the speaker: 来 = towards me (here), 去 = away from me (there).
进来 (come in, I'm inside), 进去 (go in, I'm outside), 回来 (come back here), 回去 (go back there), 上来, 下去…
With a place, it goes between the verb and 来/去: 回家去, 进教室来, 上楼来.
Examples
外面冷，快进来吧！
Wàimiàn lěng, kuài jìnlai ba!It's cold outside, come on in!
你几点回来？
Nǐ jǐ diǎn huílai?What time are you coming back?
我在楼下等你，你下来吧。
Wǒ zài lóu xià děng nǐ, nǐ xiàlai ba.I'm waiting for you downstairs, come down.
他已经回家去了。
Tā yǐjīng huí jiā qù le.He's already gone home.
Common mistakes
✗ 回来家 → ✓ 回家来.
✗ 进去教室 → ✓ 进教室去.
来 vs 去 depends on your position: on the phone from home: 你什么时候回来？