"air pollution"
"a smell of chemicals in the air"
"open a window and let in some air"
"I need some fresh air"
"her hand stopped in mid air"
"he threw the ball into the air"
"an air of mystery"
"the house had a neglected air"
"an atmosphere of defeat pervaded the candidate's headquarters"
"the place had an aura of romance"
"the breeze was cooled by the lake"
"as he waited he could feel the air on his neck"
"there was great heat as the comet entered the atmosphere"
"it was exposed to the air"
"she was humming an air from Beethoven"
"the program was on the air from 9 til midnight"
"the president used the airwaves to take his message to the people"
"air travel involves too much waiting in airports"
"if you've time to spare go by air"
"aerate your old sneakers"
"This show will air Saturdays at 2 P.M."
"We cannot air this X-rated song"
"She aired her opinions on welfare"
"Air linen"
"air the old winter clothes"
"air out the smoke-filled rooms"
We can now travel by air.
句中的by若改成through,则该加the。
Many birds are flying in the air.
I am going out for a walk in the open air.
She is on/over the air.
她正在广播。