Up to now, thousands of red phone boxes, the old image of Britain, ______ due to  mobile phones.

A．removed

B．have removed

C．were removed

D．have been removed

B淋巴细胞识别抗原的受体是（）

A.SRBC受体

B.Fc受体

C.C3b受体

D.mIg

E.TCR