根据上下文填空
--What's the ________?
--My nose hurt.
My uncle lives in Tibet. The air is quite c_______ there.
根据图示选词填空
There is ________(water/air) in the parachute.
写出所给单词的反义词
quick -- _______
dirty -- _______
根据图示填空
The air p______ comes from factories.
根据图示,将单词补充完整
a square h______
Orville Wright and his brother made the first a_________.
The h_______-air balloon rise in the air.
Some p________ are falling down.