“夺血者无汗，夺汗者无血”的理论依据是（）。

A.气能生血

B.气能化津

C.气能摄血

D.津能载气

E.津血同源

If you don't know how to read new words,            them            in dictionary. [ ]

A. look, for

B. look, after

C. look, at

D. look, up