心肌自律性最高的是()
A.心房肌
B.心室肌
C.房室交界
D.窦房结
E.心肌传导纤维
参考答案:D
Jack is late again. It is _____of him to keep otherswaiting.[ ]
A. aggressive
B. appropriate
C. desperate
D. typical
SHEL模型里面的“S”代表().
A.软件
B.硬件
C.环境
D.生命件/人