4.7.1.心动周期，心室血流充盈主要是由于
A、心室舒张的抽吸作用；
B、血液依赖地心引力而回流；
C、骨骼肌的挤压作用加速静脉回流；
D、心房收缩的挤压作用；

多项选择题遴选培训供应商时应考虑的有关问题包括供应商的（）。

单项选择题In Chapter 5 of _____, it describes the scene that a cask of wine is broke in the street. People rush in to drink every drop of it. In order not to waste the wine, they even take away the mud together with the wine. They celebrate it as if it were a holiday. A、A Tale of Two Cities B、Widower’s House C、Bleak House D、The Return of the Native