7、)21.(11分)用be动词的适当形式填空。am is aren't Are(1)—Who________yourfriend?—Myfriend________Kitty.(2)—________yourmotherfat?第10页共10页—No,she________thin.(3)—________yourmotherfat?—No,she________thin.(4)I________tall.She________short.(5)I________tall.She________short.(6)—________your