写出先张法和后张法预应力混凝土构件中预应力筋的有效预应力σpc的表达式(用σcon、σι、αE、σpcII表示)。
参考答案:
先张法:;后张法:σpe=σcon-σι。
The door opened and ________, the victim of a traffic accident.
A.Mr. Smith coming in
B.comes Mr. Smith
C.in coming Mr. Smith
D.in came Mr. Smith
Lucy said she hadn’t heard _____ music before. [ ]
A. so beautiful a
B. a beautiful
C. such a beautiful piece of
D. such a wonderful