P.R. Laws Ap. tit. 32A, § III, Rule 6.2
A party shall state in short and plain terms his defenses to each claim asserted and shall admit or deny the averments upon which the adverse party relies. If he does not have knowledge or information sufficient to form a belief as to the truth of an averment, he shall so state and this shall have the effect of a denial. Denials shall attack the substance of the averments denied. When a pleader intends in good faith to deny only a part or a qualification of an averment, he shall specify the part of it that is true and material and shall deny only the rest. A party may specifically deny each one of the averments or paragraphs of the preceding pleading, or he may make a general denial of all the averments or paragraphs of said pleading, except for the averments or paragraphs he expressly admits; but if the party intends to deny, in good faith, all the averments of the preceding pleading he may do so by general denial subject to what has been set forth in Rule 9.