题目

某研究小组发现了胎盘生长因子抗体——PLGF抗体,该抗体能与肿瘤内的胎盘生长因子结合,阻断胎盘生长因子与毛细血管结合的通路,削减了对肿瘤的养分供给,癌细胞分裂速率减缓,低于免疫系统杀死癌细胞的速率,使肿瘤明显缩小。下列说法正确的是( ) A . 人体内只有癌变的细胞内存在原癌基因 B . PLGF抗体的化学本质是蛋白质,其合成与分泌需多种细胞器的参与 C . 癌细胞容易转移,是由于细胞表面的糖蛋白增多,细胞之间的润滑作用增强 D . 该抗体与肿瘤Click and shopDo you always go shopping at the supermarket or often forget to buy something? If you do forget something, we believe you never want to go back for it. But with Webshop, our new Internet shopping service, you won’t have to. Also avoid standing so long to pay for what you get. Start shopping online now!Eat what you likeDo you usually want to avoid eating any spicy （辛辣的）food? Do you always regret drinking too much fizzy（泡沫）drinks? Well, now it’s time for you to hold a chance to change the things. You’d better take our Gasgo and begin to feel the difference!24 hours to successDo you regret not working harder at school? Do you want to improve your languages? With Polygot’s system, you can learn to speak any language in 24 hours! Try following our system and see how different it is form the rest. Why not make an early start in a class today?You’re never too old to surfDo you want to surf the Internet but think you’re too old to start learning new skills? If so, why not take some classes at CompuWia? We promise to make you master a computer whatever your age is. Don’t forget to callus before July 1st at 2839-0818, and receive a 50% lower price on lessons.1.With Webshop, you ___________.A. often forget to buy what you needB. have to stand to pay for the thingsC. can buy something you need easilyD. can call for everything you want2.If you don’t like to eat anything spicy or drink anything fizzy, you may try _________ to see how different it is.A. Polygot B. Gasgo C. CompuWiz D. Mosso3.Try to _________ and you will learn any language in a very short time.A. click on the WebshopB. call at 2839-0818C. send e-mails to friendsD. follow Polgot’s system4.You can save 50% of your money if you _________ before July 1st.A. learn surfing the Internet at CompuWiaB. hold a chance to try GasgoC. start early with Polygot’s systemD. buy something from the Webshop5.According to the passage, we can know it’s _____________.A. a piece of news B. an ad C. a story D. a survey