Most environmental problems exist because ______  measures for preventing them have not been

taken in the past.[ ]

A. accurate

B. extreme

C. tentative

D. adequate

若伤后时间超过6小时，撕脱组织瓣损伤过重，组织已不能利用，应进行

A．松解创缘，减少张力尽量拉拢缝合
B．撕脱的皮肤清创后，切削成全厚或中厚皮片再植
C．立刻做血管吻合组织再植术
D．采用局部皮瓣关闭创面
E．切取健康组织皮片游离移植消灭创面