第8题: [单项选择]______ most of the earth's surface is covered by water, fresh water is very rare and precious. A. As B. Once C. If D. Although 参考答案:D 答案解析:本题考查的是连词的用法。根据句意应选择表示让步的连词，因此选择Although。本句的意思是：“尽管大部分地球表面被水覆盖，但是淡水还是很少、很珍贵。”
A. shorten the duration of the illness B. the patient buy medicine over the counter C. the patient obtain cheaper prescription drugs D. prevent people from catching colds and the flu 参考答案:A 答案解析:[解析] 细节题。根据第一段“but being able to tell if the cause is a cold or flue may make a difference in how lo
