Show that exist a finite set of clauses F in first-order logic that Res*(F) is infinite


I’m kind of desperate at this point about this question.

A predicate-logic resolution derivation of a clause $ C$ from a set of clauses $ F$ is a sequence of clauses $ C_1,\dots,C_m$ , with $ C_m = C$ such that each $ C_i$ is either a clause of $ F$ (possibly with the variables renamed) or follows by a resolution step from two preceding clauses $ C_j ,C_k$ , with $ j, k < i$ . We write $ \operatorname{Res}^*(F)$ for the set of clauses $ C$ such that there is a derivation of $ C$ from $ F$ .

The question is to give an example of a finite set of clauses $ F$ in first-order logic such that $ \operatorname{Res}^*(F)$ is infinite.

Any help would be appreciated!