【简答题】病毒是严格的 __,它只能在__ __内繁殖,其繁殖过程可分为__ _、___ __、_ ___、______和_____五个阶段。
【单选题】听力原文: It was not until one hundred and fifty years ago that scientists learned about the existence of dinosaurs. Thanks to an English doctor and his wife, the door was opened to this zoological study....
【简答题】Although man has known asbestos (石棉) for many hundreds of years, it was not until 160 years ago that it was mined for the first time on the North American continent. H.W.Johns, owner of a New York Cit...
【单选题】Bach died in 1750,but it was not until the early 19th century his musical gift was fully recognized.
【单选题】It was not until the 4th century ( ) the church in Rome began to celebrate Christmas.