Parents ________ much importance to education.They will do their best to give their children that

priceless gift. [    ]

A. attach  

B. pay

C. link  

D. apply

强心苷治疗心衰的药理学基础是（）。

A.抑制房室传导

B.加强心肌收缩力而不增加耗氧量

C.抑制窦房结

D.缩短心房的有效不应期

E.增加房室结的隐匿性传导