时间特征是指文件内容所针对的时间和（）时间共同构成的特征。
参考答案：文件形成
Mr. Smith, who often helped passers-by repair their bikes, said that what he did was not paid but _______.
A．relevant
B．optional
C．suitable
D．voluntary
监理实施细则的编制对象是()。
A．监理规划
B．项目整体
C．监理合同
D．专业监理工作
