单项选择题 听力原文:W: Gosh! Fred. Another cup of coffee? That's your third since lunch.M: Yeah. Well, I stayed up all night cramming for my history exam. I couldn't keep my eyes open in my last class. I'm having this coffee so I can stay awake this afternoon.W: Don't you know that drinking too much coffee is harmful?M: What do you mean harmful?W: Well, for one thing, it may cause heart disease.M: Nah. Most of the research about the link between coffee and heart disease is inconclusive.W: But coffee has caffeine which is addictive.M: You can't become addicted to caffeine like other drugs.W: Yes, you can. Don't you know that people who are deprived of caffeine suffered withdraw symptoms especially headaches.M: One cure for headaches, oddly enough, is caffeine. Haven't you ever noticed that many over-the-counter headache remedies use caffeine as one of their ingredients?W: Besides, coffee helps me work faster.M: Studies have shown that coffee makes you work faster, but not necessarily better. You may finish your exam in a shorter period of time but you won't have fewer errors.M: You know, that soda you're drinking has caffeine in it too.M: But twelve ounces of soda has only half the caffeine of a five ounces cup of coffee. And a cup of tea has less than that.M: But I like the taste of coffee.W: You could drink decaf.M: Decaffeinated coffee doesn't have as much flavor or body as regular coffee. Besides, I want something that will keep me alert in class. what is the conversation mainly about?A.The effects of. caffeine.B.Some causes of headaches.C.How to do well on exams.D.Problems with the student cafeteria.
单项选择题 今年M市开展了一次前所未有的化妆品广告大战。但是调查表明,只有25%的M市居民实际使用化妆品。这说明化妆品公司的广告投入有很大的盲目性。 以下哪项陈述最有力地加强了上述结论?()
单项选择题 只有具备足够的资金投入和技术人才,一个企业的产品才能拥有高科技含量。而这种高科技含量,对于一个产品长期稳定地占领市场是必不可少的。 以下哪种情况如果存在,最能削弱以上断定?()