哪一种维生素在吸收过程中需要胃粘膜分泌的内因子协助（）
A.维生素E
B.维生素D
C.维生素C
D.维生素B12
E.维生素B6
参考答案：D
The old lady has a _______ time _______ clothes every day.
A．difficulty; to wash
B．difficulty; washing
C．difficult; to wash
D．difficult; washing
护理质量标准规定，对手术室医护人员的手进行微生物监测的周期是( )
A．每周 B．每月C．每天 D．每2周
