SAXOPHONE QUESTION, PLZ HELP, GOT ESSMENT TMRW! EAST 10 PTS, PLZ HELP ME A.S.A.P PLZ I NEED YOUR HELP PLZ!!?

MY SAXOPHONE SOUNDS A BIT SQUEAKY WHEN I PLAY THE HIGH NOTES LKE D, E, AND F. HOW CAN I GET THE SOUND MORE CLEAR AND NOT SQUEAKY. PLEASE HELP ME, ILL GIVE 10 POINTS TO THE FIRST HELPFUL ANSWER!!!