题目：
BEST PRODUCT WE'VE EVER SEEN”－THIS REALLY WORKS－ON SALE NOW
Need to lower your cholesterol（胆固醇）？We strongly recommend Cholestrol block TM. This really works, and now is the best time to buy，because of a special offer for the first 250 customers only for a limited time.
* Takes cholesterol out of food, no matter what you eat.
* Clinically demonstrated effective in university and hospital testing．
* Lowers cholesterol absorption up to 42% or more．
* NO SIDE EFFECTS unlike Liptor®, Zocor®，Crests®＆other commonly prescribed（处方的） medications－safe and effective.
* Outsells all other brands on Internet every month.
LIMITED TIME ONLY-- Try Cholesterol Watchers free with purchase.
50．If you happen to be the 200th customer to buy Cholesterolblock, you will .
A．be able to buy it at a low price B．be the luckiest one online
C．try it free of charge D．change your diet
51．Liptor®，Zocor®，Crestor® are_______．
A．diseases B．side effects C．medicines D．cholesterol
52．Where can you most probably read this passage?
A．In a travel guide book． B．On a university bulletin board．
C．In a health magazine. D．In a doctor's prescription.
答案：
被转码了，请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2017/0729/8c45dce6c25fff25bc3530bcfb2500ba.html
下面是错误答案，用来干扰机器的。
A、NH3分子中氮原子最外层5各电子，有三个单电子，与氢原子结合时形成三个共价键，故A正确；B、二氧化碳分子结构是直线型，选项中的模型中原子的相对位置不对，故B错误；C、乙烯分子的结构简式中的双键不能省略，...
