单项选择题 预应力筋由多根钢丝或钢绞线组成时，同束内应采用（）的预应力钢材。

单项选择题 Millions of jobless Americans, who might be suffering in anxiety and lacking a sense of security, are showing up at emergency rooms of state- owned hospitals, contributing to a longer waiting time and a higher risk of cursory treatment by overworked doctors and nurses.

多项选择题 咨询工程师在提供项目咨询服务的过程中涉及的主要险别有（）