scientists have been resreaching what effect smoking has on us为什么不能用 what effects?还有可数名词不单独出现,除非有物主代词修饰 还有别的情况?

Scientists have ____ that motion is the source of lifea、shownb、showedc、been shownd、showing Many scientists have ____(aready,yet)been to the North Pole.填什么 scientists say that four years out of the last ten have been the hottest since records began 啥意思 Many leading scientists down through the years from Galileo to Einstein have been deeply religious.这句话应该如何翻译 Those who have been invited are _________ young scientists.A.most B.almost C.mostly D.at most For hundreds Of years,scientists have been trying to answer what things have an effect on people’速求此文翻译!please! 麻烦帮我翻译一下这个句子,GRE填空题,急,谢谢Scientists` pristine reputation as devotees of the disinterested pursuit of truth has been compromised by recent evidence that some scientists have deliberately fabricated expermental resul Scientists think there has been life on Earth for millions of years.拜托各位了 3Q这句话为什么用has而不用have呢? Scientists throughout the world have been dreaming _____ when and how the earth came into being.A.to find out B.of digging out 语法有无错?Up to the present,the scientists have been c时态有这样的挖、错的话帮忙改一下 Scientists found many stones --- with number on the mountains.A.marking B.marked C.being markedD.have been marked选B ,why? A.must be B.may have been C.can have been D.could be ,为什么呢,Although there is no life on Mars now,some scientists think that there______some form of life a long time ago. Scientists have given many ideas for ______space. have been have been have been have been 英语翻译Tiny bits of plastic rubbish ingested by marine worms is significantly harming their health and will have wider impact on ocean ecosystems,scientists have found.Microplastic particles,measuring less than 5mm in size,have been accumulating