外科感染的特点不包括()。
A.病变以局部炎症为主
B.多数由单一细菌引起
C.多数与创伤有关
D.常需要手术治疗
E.可分为非特异性感染和特异性感染
参考答案:B
We have a laptop at home, but I ______ it. [ ]
A. often use
B. don't often use
C. doesn't use
D. often don't use
某种群中年轻的个体非常多,年老的个体很少,这样的种群密度会()
A.越来越大
B.相对稳定
C.越来越小
D.绝对不变