The two strangers talked as if they ______ friends for years.A．should beB．would beC．have b

He is talking so much about America as if he ____ there.A、had beenB、has beenC、wasD、been

He talks as if he______ everything in the world.A．knowsB．knewC．had knownD．would have known

He talks as if he ______ everythingA．knowsB．was knownC．will knowD．knew

The way we speak to close friends is often not the same as the way we speak to strangers,

If two sounds in a language make a contrast between two different words, such as[t]in tie

Scientists have wondered for a long time if animals can learn to talk as human beings do.