One-trick pony

    一招鲜

    A: They have just announced that Robert will be overseeing the new project.

    B: He is young, but certainly he's not a one-trick pony.

    Note: A one-trick pony is a small horse that has one skill and one skill only. It is no good at anything else. This expression, American in origin, is said to have derived from shabby circus shows in rural America in the 19th century. They had horses and dogs pulling carts and running circles, plus a few clowns bouncing around and little else. Hence, these shabby shows were known as one-trick pony shows. If you say someone is a one-trick pony, you mean that their skills are few and limited.