He's been dead for 5 years, ______? [ ]
A.isn't he
B.wasn't he
C.didn't he
D.hasn't he
答案:D
易积灰的屋面,宜采用刚性材料作保护层。( )
下列最不易被皮肤吸收的维生素是()
A.维生素C
B.维生素K
C.维生素E
D.维生素D
E.维生素A