Three years have ______ since we last met at the conference for Internet communication in

To trace the ______ of the Irish problem, we have to go back over three hundred years.A．bi

We______each other since our boyhood.A．knewB．have knownC．will have knownD．will be knowing

General elections in New Zealand have been held about every______years since 1879.A．threeB

Visitors from the US have increased______8 percent since last year.A．inB．byC．withD．from

Ever since we moved to South Florida two years ago, we______fresh clean air.A．had been enj

We will be losing money this year______our new plan works well.A．ifB．unlessC．sinceD．until