公共关系的主体：
参考答案：公共关系的主体：是指公共关系活动的组织者、发动者。
个人网上开户提交申请后，提示“客户号已被使用”时怎么办？
There ______ some paper and three books in his backpack. [ ]
A. isn't
B. aren't
C. is
D. are
