尚可耐受中型手术的轻度肺功能不全,其最大通气量是()。
A、90%~100%
B、75%~90%
C、60%~70%
D、40%~60%
E、小于40%
参考答案:C
—Excuse me, does Mr. Chen live here?
—He ______ be here, but he has moved to Nanjing.
A.used to
B.happened to
C.tried to
D.had to
当材料受力(大)后,变形与力不成正比,变形增长率比受力增大率快,一旦卸荷,虽会恢复大部变形,但尚留少部残余变形,该状态是()。
A.弹性状态
B.塑性状态
C.拉伸状态
D.压缩状态