简介:请先阅读下面这篇短文,注意斜体句子的结构。(1)TodayitisAmericansciencethatleadstheworld,butwehavenoassurancethatthisstateofaffairswillcontinue.TheUnitedStatesisrunningshortofpeopletrainedinscience,whilethenumberofourscientistshasmultipliedmanytimesover,andthedemandforscientificskillshasbeenincreasingevenfaster.