心肌细胞有效不应期特别长的生理意义是()。
C
心肌兴奋性变化的特点是有效不应期长，相当于整个收缩期和舒张早期，这一特点使心脏不会发生完全强直收缩，始终保持收缩与舒张交替的节律活动，心脏的充盈和射血才可能进行。
AccordingtoStevenYoung,ifscientistsgetthedatathat________,theywouldpetitionforfasttrackstatus.
Bysaying"thegrowthoftheproportion...toyoungergenerations."(Line2,Para.5),AntheaTinkerreallymeansthat________.
_____yourtimelyadvice,Iwouldneverhaveknownhowtogoaboutthework.
Thebesttitleforthepassagewouldbe________.