Am and fat are pronounced the same as A. They are both short vowels of vowel letter A. The vowel letter A is pronounced short in stressed closed syllables. When pronouncing, the tip of the tongue is close to the lower teeth, the front of the tongue is raised, and the tongue position is low, which is the lowest among the four front vowels, but the one with the largest opening belongs to the short vowel, but it has a considerable length in actual pronunciation. The gums are between half-open and open, and the lips are not round. This sound mainly appears in the position of prefixes and characters.