— What is that noise?

— Oh, I forgot to tell you that the new machine_____   .[ ]

A. was tested

B. will be tested

C. has been tested

D. is being tested

慢性支气管炎的病理变化有（）

A.支气管粘膜上皮变性、坏死、增生及鳞状上皮化生

B.管壁慢性炎性细胞浸润及纤维化

C.管壁平滑肌束断裂、萎缩

D.软骨变性、萎缩、钙化或骨化

E.腺体增生、肥大、粘液化和退变