题目

Roses are quite _____ flowers in English gardens.         A. ordinary    B. common    C. usual    D. general 答案：  B 解析: common(=usual and ordinary; happening of found often and in many places)普通的；常见的；常常发生的；到处可见的：a common experience(普通的经历)；a common tree(常见的树木)。This bird is common throughout Europe.(这种鸟在欧洲很常见。)They can treat most of the common diseases.(他们能治疗大多数常见病。)usual(=done, found, used or exis下列生物体内肯定不存在A –T碱基对的是 A．烟草花叶病毒        B．大肠杆菌             C．T2噬菌体               D．玉米