和【hé】

和 joins two nouns, or the last two items of a list. Earlier items in a list are separated by 、.

和 does not join clauses

English "and" links clauses freely; 和 does not. Two clauses sit side by side with a comma, or are linked with 然后, 也 or 而且.

• × 我去学校和他去公司 → 我去学校，他去公司

In everyday speech 和 doesn't join adjectives or verbs either. Two adjectives take 又…又….

• × 他很高和瘦 → 他又高又瘦

Formal writing does join pairs of two-syllable verbs with 和, as in 研究和讨论.

和 as "with"

Before a verb, 和 marks the person you do something with, often together with 一起. 跟 does the same job and is more colloquial.