(1) This figure shows diaphragm contraction. At this time, the diaphragmatic roof descends, the chest volume expands, and the lungs expand accordingly, resulting in the air pressure in the lungs being lower than the outside atmospheric pressure, and the outside air enters the lungs, which is an inhalation process.

(2) A stands for trachea, B stands for bronchus, C stands for lung, D stands for thoracic cavity and E stands for diaphragm.

(3) When the rubber film is pulled down by hand, the volume of the bell jar increases, the internal air pressure decreases, and the balloon expands. The air pressure in the balloon is lower than the atmospheric pressure, and the air entering the balloon indicates inhalation, so this figure shows the inhalation process.

So the answer is: (1) Inhale; (2) trachea; Bronchus; Lung; Diaphragm; (3) getting bigger; Inhale; The air pressure in the lungs is below atmospheric pressure.