Never before______ so highly successful in his attempts to forecast the weather accurately on a small scale．

A．man has been

B．man is

C．has man been

D．will be man

家族性良性慢性天疱疮在组织学中水疱位于（）

A.表皮内

B.表皮下

C.角质层

D.真皮内

E.真皮 * *