With the development of modern society, E-mail as well as telephones     an important part in daily communication.

A．have played

B．is playing

C．are playing

D．had played

目前还未发现艾滋病可通过下列哪一方式传播（）

A.共用针头或注射器

B.医务人员被含血针头刺伤

C.应用病毒携带者的器官移植

D.人工授精

E.吸血昆虫