溃疡病病理变化镜下观是
A.坏死层十肉芽组织层B.坏死层十炎症层C.炎症层+疤痕层D.肉芽组织层+疤痕层E.坏死层+炎症层+肉芽组织层+疤痕层
参考答案:E
Paul doesn't have to be made . He always works hard, [ ]
A. learn
B. to learn
C. learning
D. learned
对污染物在大气中的扩散和稀释起着决定性作用的气象因素是()
A.风和湍流
B.气温
C.气湿
D.气压
E.热辐射