I don't like that book. It's too ______ . [ ]
A. interesting
B. exciting
C. difficult
答案:C
一切材料都因外力作用而产生变形。
在肌小节中间形成终末池,可储存、释放钙离子的是()。
A.肌原纤维
B.肌管系统
C.横管系统
D.纵管系统