（）在工程项目施工中处于中心地位，对于工程项目施工负有全面管理的责任。
A. 技术负责人
B. 承包单位
C. 企业法人
D. 项目经理
Not until my British friend came to China（）how densely populated the country is.
A. did he realize
B. he didn't realize
C. he realized
D. he could realize
彩色血流图是指
A. 振幅调制型
B. 辉度调制型
C. 彩色血流显像
D. 多普勒频谱显示
E. 活动显示型
One important aspect the old should learn from the young is that ______.
A. they should fully enjoy life and reject worries
B. they should expect a better future and cherish the hard past time
C. they should try to integrate leisure in work
D. they should learn to indulge in material life
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