组成条码的每一符号字符都是由 4 个条和 4 个空共 17 个模块构成，所以称为()条码。
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在变量、取值相异时，其逻辑函数值为1，相同时为0，称为异或运算()
房地产商业信用是指企业之间相互提供的与房地产交易直接相联系的信用。()
It can be inferred from Para. 4 that______.
A. all universities in America have offered online counseling services
B. parents play a vital role in solving students" mental-health problems
C. University of Minnesota took the initiative to give lectures on mental health
D. Philadelphia University used a calendar as the reminder of diagnostic quizzes
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