[填空题]
A person standing a certain pklnx/xj7 bw90co-u+d mj4v6 distance from an airplane wit s,x+s)7nbsd latu 2-zh four equally noisy jet engines is experiencing a sound level borderisx z ,sb+-na2u7t)lsd ng on pain, 120 dB. What sound level would this person experience if the captain shut down all but one engine? [Hint: Add intensities, not dB’s.] dB
