Why are you looking at me in _____surprised expression─ Don’t you think _____ question you askedis surprising

Here _______ two nice photos of my family.

Must I turn off the gas after cooking ? –Of course You can never be ___ careful with that

st decade of the 21st century________ the rapid, steady development of China in various fields.

Every possible means ________ to prevent the air pollution，but the sky is still not very clear.