A.10° B.15° C.20° D.25°
A.預(yù)應(yīng)力鋼筋混凝土桿和普桿 B.預(yù)應(yīng)和錐型桿 C.錐型桿和普桿 D.有預(yù)應(yīng)力鋼筋混凝土桿和部分預(yù)應(yīng)力鋼筋混凝土桿
A.停止 B.安排 C.改變 D.撤銷