贝多芬是哪国的作曲家？
参考答案：
德国
洋金花中含有的生物碱有（）
A.东莨菪碱
B.N-去甲基菪碱
C.莨菪碱
D.黄连碱
E.药根碱
In software engineering and systems engineering, (71) is a description of a system's behavior as it responds to a request that originates from outside of that system．
A．black box B．business ruleC．use case D．traceability matrix
