若术中见疝囊内部分肠管发黑、坏死属于
A．易复性疝B．难复性疝C．嵌顿性疝D．绞窄性疝E．混合性疝
参考答案：D
You had better ________ some time every day for sports so that you can keep yourself energetic.[ ]
A. set aside
B. take up
C. put away
D. give out
X射线探伤的优点是显示缺陷的灵敏度高，特别是当焊缝厚度小于( )时。
A．10mm
B．20mm
C．30mm
D．40mm
