单价合同大多用于工期长、技术复杂、实施过程中发生各种不可预见因素较多的大型复杂工程的施工,以及业主为了缩短项目建设周期,初步设计完成后就进行施工招标的工程。()
参考答案:对
— Go and ask the waiter how much _____.
— Don't worry. It has been _____. [ ]
A. does the meal cost, paid for
B. the meal costs, paid
C. the meal spends, paid
D. the meal costs, paid for
内防喷工具主要指()。
A.方钻杆上旋塞
B.方钻杆下旋塞
C.箭形止回阀
D.浮阀
E.节流阀