下列计算正确的是[ ]
A.a3a4=a12
B.(a2b)3=a6b3
C.(a3)4=a7
D.a3÷a4=a
答案:B
The population of China ________ 1.3 billion,and 80% of the population________farmers.
A.are; is
B.is; is
C.is; are
D.are; are
肾综合征出血早期出血的原因主要为 ()
A.尿毒症致凝血功能异常
B.类肝素物质增多
C.血管壁脆性增加及血小板减少
D.血管因子消耗缺乏
E.播散性血管内凝血