按照沟通的渠道不同，沟通可分为（）。

balcony baggage back barrier balance bargain basis bad beat before1. The magazine is a ________ number. You can take it out of the reading-room.2. Too much salt can be _______ for you.3. Two pieces of _______ went missing at the railway station.4. I lost my __________ and fell on my face.5. My flat has got a _______, where I can stand and watch the sea6. Some people would like to do shopping on Sundays since they expect to pick up wonderful __________ in the market.7. Problems with childcare remain the biggest ________ to women succeeding at work.8. In Iraq nowadays, plenty of people are short of ______necessities like food, water, and medicine.9. The room was so quiet that I could hear the ________ of my heart.10. The roof fell ________ he had time to rush into the house to save his baby. 点击查看答案

在疟疾流行的地区，很多孩子在感染疟疾几次后才对疟疾具有免疫力。显然，孩子的免疫系统在受到疟原虫的一次攻击后，只能产生微弱的反应，而必须被攻击多次后才能产生有效的免疫反应。以下哪项如果为真，最严重地削弱了上面的假设？（）

A．在一个孩子一旦感染疟疾后，孩子的监护人提高了避免使孩子再次感染疟疾的警惕，但是这种警惕过不了多久就降低了
B．疟疾有几种截然不同的类型，人体对某一类型疟疾的免疫力并不能保护人免受其他类型疟疾的攻击
C．某一种基因如果可以从孩子的父母之一那里遗传下来，则可以使孩子对疟疾产生免疫力
D．治疗疟疾的疫苗都是通过激发人体的免疫力来发挥作用的

点击查看答案&解析