心肌收缩能力的增强可通过下列哪一途径实现
A.增加参与收缩的肌纤维数目B.增加肌小节的初长度C.增加兴奋时肌质内Ca2+浓度D.心肌发生完全强直收缩
参考答案:C
为了提高测试的效率,应该( )。
A.随机选取测试数据
B.取一切可能的输人数据作为测试数据
C.在完成编码以后制定软件的测试计划
D.集中对付那些错误群集的程序
The table above shows the cost, in dollars, of traveling to and from cities A, B, C, D, E, and F. A sales representative wants to leave from A, travel to C, E, and F, and return to A. If the first city that the sales representative travels to must be E,what is the minimum possible cost for the entire trip ?()