I The trial court has no jurisdiction to hear and try Civil Case No. Q-93-18394 based on Article 21 of the New Civil Code since the proper law applicable is the law of the Kingdom of Saudi Arabia inasmuch as this case involves what is known in private international law as a conflicts problem. Otherwise, the Republic of the Philippines will sit in judgment of the acts done by another sovereign state which is abhorred. II. Leave of court before filing a supplemental pleading is not a jurisdictional requirement. Besides, the matter as to absence of leave of court is now moot and academic when this Honorable Court required the respondents to comment on petitioners April 30, 1996 Supplemental Petition For Review With Prayer For A Temporary Restraining Order Within Ten (10) Days From Notice Thereof. Further, the Revised Rules of Court should be construed with liberality pursuant to Section 2, Rule 1 thereof. III. Petitioner received on April 22, 1996 the April 10, 1996 decision in CA-G.R. SP NO. 36533 entitled Saudi Arabian Airlines v. Hon. Rodolfo A. Ortiz, et al. and filed its April 30, 1996 Supplemental Petition For Review With Prayer For A Temporary Restraining Order on May 7, 1996 at 10:29 a.m. or within the 15-day reglementary period as provided for under Section 1, Rule 45 of the Revised Rules of Court. Therefore, the decision in CA-G.R. SP NO. 36533 has not yet become final and executory and this Honorable Court can take cognizance of this case.xxxiii[33] From the foregoing factual and procedural antecedents, the following issues emerge for our resolution: I. WHETHER RESPONDENT APPELLATE COURT ERRED IN HOLDING THAT THE REGIONAL TRIAL COURT OF QUEZON CITY HAS JURISDICTION TO HEAR AND TRY CIVIL CASE NO. Q-93-18394 ENTITLED MILAGROS P. MORADA V. SAUDI ARABIAN AIRLINES. II. WHETHER RESPONDENT APPELLATE COURT ERRED IN RULING THAT IN THE CASE PHILIPPINE LAW SHOULD GOVERN. Petitioner SAUDIA claims that before us is a conflict of laws that must be settled at the outset. It maintains that private respondents claim for alleged abuse of rights occurred in the Kingdom of Saudi Arabia. It alleges that the existence of a foreign element qualifies the instant case for the application of the law of the Kingdom of Saudi Arabia, by virtue of the lex loci delicti commissi rule.xxxiv[34]