— What are these?                             

— _____ are scissors. [ ]

A. They                                         

B. Those                       

C. This                                              

D. That

类风湿性关节炎关节的基本病理改变是()

A．滑膜炎

B．血管炎

C．关节囊、韧带及肌腱附着点炎

D．软骨变性

E．类风湿性肉芽肿