桥涵用钢的基本技术性能有哪些?
参考答案:
(1)强度,即屈服强度与抗拉强度;
(2)塑性,即伸长率与断面收缩率;
(3)硬度;
(4)冲击韧性;
(5)冷弯性能;
(6)焊接性能。
You'd better _______ your hands to help him when someone is in trouble. [ ]
A. put away
B. put out
C. take out
D. put up
胃粘膜分泌盐酸的壁细胞分布于胃的()
A.贲门部
B.胃体部
C.胃底和胃体
D.胃底和胃窦部
E.胃体和胃窦