It is appropriate to; (2) It is customary for x to; (3) It is doubtful that; (4) It is impossible; (5) It is unlikely that; (6) It is no secret that; (7) It should be emphasized that, (8) It should be stated that, (9) It was understood, (10) It was therefore clear that, (11) It was confirmed and agreed that; (12) It goes without saying that