本来【běnlái】

本来 describes how things were, or what someone meant to do, before something changed. It goes before the verb, either side of the subject, and a second half with 可是, 但是 or 后来 says what changed.

With a plan, 本来 usually comes with 想, 打算 or 要.

本来就 for "of course"

本来就 says something was true from the start and was always going to be: "of course", "anyway", "to begin with". It often answers a complaint or a surprise.

本来 or 原来

原来 can also mean "originally", but its main use is a discovery: "so that's it". 本来 never means that.

• × 本来是你！ → 原来是你！

Before a noun, 本来的 means "original": 本来的计划, "the original plan".