layman

To the layman (= laymen in general ) all these plants look pretty similar.

对外行的人来说，这些植物看起来都很相似。

If you don’t understand what the doctor says, ask to have it explained in layman’s terms (= in simple language ).

如果你听不懂医生的话，就请他用通俗易懂的语言来解释一下。