互相【hùxiāng】

互相 means "each other". It is an adverb, so it goes before the verb, and the subject has to be plural – two people, or a group.

Nothing after the verb

In English "each other" is the object. In Chinese 互相 already says who does what to whom, so the slot after the verb stays empty of any "each other" word.

• × 我们帮助互相 → 我们互相帮助
• × 他们互相喜欢他们 → 他们互相喜欢

The verb can still take an ordinary object: 互相学习汉语 is fine, because 汉语 is what is learnt, not who.

The verb after it

互相 sits best with a two-syllable verb: 帮助, 学习, 关心, 了解, 认识. A one-syllable verb usually takes something after it – 了, a reduplication or an object – rather than standing bare.

With 不

不 goes after 互相.

彼此 also means "each other" and is more written; it can stand as a noun (彼此的), which 互相 can't.