our research has been constrained by lack of funding为什么要用has been 可以用was吗

Scientific research has a great influence on our society.16 the one hand we . his research has contirbuted greatly ------our understanding of this disease 填介词 our research has been constrained by lack of funding为什么要用has been 可以用was吗 There is a bee in our classroom .During the past two decades,research has ________ our knowledge of daydreaming.A.expanded B.emeDuring the past two decades,research has ________ our knowledge of daydreaming.A.expanded B.emergedC.descended D.conquered 翻译Our research has focused on a drug which is so powerful as to be able to change brain chemistry he has a bee in his head 急用 Since our research so far has not produced any answers to this problem,we need to try a different ______ to it.1.way2.means3.approach4.manner research Research research a research shows that expressions on our faces 做一下这几个英语大专试题31． “Did you say that our neighbor ____ in the accident?”A badly hurt B was badly hurted C was badly hurt D had badly hurted.32．She ought to stop work ; she has a headache because she ____too long.A has bee 谁来帮我讲讲这句话的语法结构The process by which we store and retrieve information in our brains has been the focus of scientific research for many years. 这里为什么用 (has bee chosen)而不是is you should tell tom that he (has bee chosen) to work for这里为什么用 (has bee chosen)而不是is chosenyou should tell tom that he (has bee chosen) to work for Nanjing TV station.i think so ,I will It __ and the streets were still wet.A.rained B.has bee raining 英语翻译Man has done much research in our universe.Man has even invented four kinds of satellites.The first kind of satellite studies the geography of 1 ,our home.It is used to make maps and also help countries to see where they may 2 oil ahd gol 英语翻译For your information,I enclose also some of the pictures reminding you our stay in your Farm.But be so kind and send us by regular mail all the pictures (photos) presenting the manifold art activities of Mr.Jaroslav Sindelar,which has bee