There was a hole in the door, through which I 　　　 sight of Mr. Brown sitting in a chair. 

A．caught

B．made

C．took

D．got

系膜细胞来源于（）。

A.成纤维细胞

B.毛细血管内皮细胞

C.平滑肌细胞

D.足细胞

E.以上均不是