题目

---- What is the _______ between the two men?          ---- They are colleague(同事). Their job is to collect _______ important information for the boss.          A. relationship; every day     B. friendship; everyday          C. relationship; everyday      D. friendship; every day 答案：C10、人体皮肤的屏障作用，呼吸道、消化道黏膜能分泌杀菌物质，这是人体免疫的(    ) A．第一道防线     B．第二道防线     C．第三道防线     D．前两道防线