[单选题]By the time you come back, your aunt ________ for Nanjing to attend a meeting.A. will leaveB. leavesC. will have leftD. left
[单选题]下列作法对人体健康不会造成危害的是( )A.用福尔马林浸泡海产品,防腐保鲜B.将含有甲醇的工业酒精兑制成饮用白酒C.食盐中加入一定量的碘单质可制成食用加碘盐D.乙酸可以用作生活调味品
[单选题]下列说法不正确的是A.为了提高生活用水的卫生标准,自来水厂常同时使用Cl2和FeSO4·7H2O进行消毒、净化,以改善水质B.铝表面有一层致密的氧化物薄膜,故铝制容器可用来腌制咸菜等C.从分类的角度看,混合物、分散系、胶体的从属关系如图所示:胶体分散系混合物D.借助扫描隧道显微镜,应用STM技术可实现对原子或分子的操纵
[单选题]石油裂化的主要目的是[ ]A.使长链烃分子断裂为短链烃分子B.除去石油中的杂质 C.提高汽油的产量和质量 D.使直链烃转化为芳香烃
[单选题]下列叙述中,不正确的是( )A.天然药物无毒副作用,适合任何人群服用B.食品中加入调味剂的量是有严格规定的,摄入过多对人体有害C.纤维素在人体内不能水解成葡萄糖,不能作为人类的营养物质D.糖类、油脂、蛋白质、维生素、无机盐和水是人体所需的六大营养素
[单选题]—I have not finished with my dinner yet.—But our friends ______ for us.A.will waitB.waitC.have waitedD.are waiting
[单选题]下列营养物质在人体内发生的变化及其对生命活动所起的作用叙述不正确的是 [ ]A.淀粉葡萄糖CO2和H2O(释放能量维持生命活动) B.纤维素葡萄糖CO2和H2O(释放能量维持生命活动)C.油脂甘油和高级脂肪酸CO2和H2O(释放能量维持生命活动)D.蛋白质氨基酸人体所需的蛋白质(人体生长发育、新陈代谢)
[单选题]I dont really work here; I ____ until the new teacher arrives. ( )A. just help out B. am just helping outC. have just helped out D. will just help out
[单选题]下列说法中正确的是( )A.维生素A可防止坏血病,胡萝卜和鱼肝油中含量较高B.维生素C(如图)又称视黄醇,属于脂溶性维生素,具有较强的还原性OCH2-CH-CHC=0OHOHC-COHOHC.富含维生素C的食物应在高温下烹调,才能充分提高维生素C的功能D.维生素D可促进Ca2+的吸收,防止佝偻病,软骨病
[单选题]下列有关油脂的说法中正确的是[ ]A.混甘油酯为混合物B.油脂水解后的产物中,主要是甘油为人体提供能量C.相同质量的油脂提供的热量比葡萄糖少 D.形成油脂的脂肪酸的饱和程度影响油脂的熔点
[单选题]海水中所含的化学资源中最多的是( )A.钾和硫B.钙和溴C.钠和氯D.铀和金
[单选题]-Hi,Tracy,you look tired. -I am tired.I____ the living room all day. [ ]A. painted B. had painted C. have been painting D. have painted
[单选题]有人认为人体是一架缓慢氧化着的“高级机器”,人体在生命过程中也需要不断地补充“燃料”.按照这种观点,你认为人们通常摄入的下列物质不能看作“燃料”的是( )A.淀粉类物质B.纯净水C.脂肪类物质D.蛋白质
[单选题]The time I had been looking forward to ________ at last and I saw my favourite star.[ ]A. comingB. having comingC. cameD. come
[单选题]This machine _____. It hasnt worked for years. ( )A. didnt work B. wasnt working C. doesnt work D. isnt working
[单选题]下列有关物质制备的说法中正确的是[ ]A.工业上通过电解MgO制取镁B.工业上通过向浓缩的海水中通入氯气获得碘 C.工业上主要通过高温冶炼黄铜矿获得铜D.工业上用二氧化锰与浓盐酸制备氯气
[单选题]After he retired from office, Rogers_______ painting for a while, but soon lost interest.A.took upB.saved upC.kept upD.drew up
[单选题]Soon all the people at the meeting_____ on the discussion of developing the local education.A.collectedB.concentratedC.agreedD.concerned
[多选题]有关柠檬的说法正确的是( )A.柠檬是具有酸味的食物B.柠檬是酸性食物C.柠檬是碱性食物D.柠檬含有丰富的维生素
[单选题]---I hear Liza and her husband have flown to Hawaii for their honeymoon.---Oh, how nice! Do you know when theyA.were leaving B.had left C.have leftD.left
[单选题]My parents?______ in Hengshui. They were born there and have never lived anywhere else. [ ]A. live B. lived C. were living D. will live