He is a student at Oxford University,_______ for a degree in computer science.

A．studied

B．studying

C．to have studied

D．to be studying

以下哪项是虚证闭经的主要病机 （）

A.肝肾不足，冲任失养，无以化为经血

B.脾虚血少，血海空乏，无血可下

C.精血不足，血海空虚，无血可下

D.阴虚血燥，血海燥涩干涸，无血可下

E.虫积耗血，冲任大虚，血海空乏