John is my _____friend of all the classmates.

The couple _____ for thirty years

New digital mobile phones definitely produce less radiation, but that doesn’t mean that they should be used without caution.

－Linyi has changed a lot in the past few years.－Yes. You can see a lot of buildings, trees on ________ sides of the streets.

Burns are called first，second or third degree burns，which layers of the skin are burned.