胸痹阴寒凝滞证，其临床特点是（）

A.胸部刺痛，入夜尤甚

B.胸闷隐痛，时作时止

C.胸闷如窒，气短喘促

D.胸闷气短，畏寒肢冷

E.胸痛彻背，感寒痛甚

Modern technology has brought us so much convenience--we can now do many things

Through        we call the Internet．

A．how

B．what

C．which

D．that