“上气不足”出自于（）。

A.《丹溪心法.头眩》

B.《素问.玄机原病式.五运主病》

C.《灵枢.海论》

D.《素问.至真要大论篇》

E.《灵枢.口问篇》

—We can use QQ to communicate with each other online.

—Good. Will you please show me         ?

A．which to use

B．how to use it

C．what to use

D．where to use it