Thomas Edison ____ already ____ a chemistry lab for himself by th_英语解答

Thomas Edison ____ already ____ a chemistry lab for himself by the time he ____ ten.
A.has…built…was B.had…built…was C.would…build…was D.was…building…is

人气：492 ℃　时间：2020-03-26 05:09:50

解答

B,因为从句是一个过去时,所以主语是发生在过去的过去,所以用过去完成时.