李欣经常偏食，结果他的上皮组织发生了角质化，皮肤粗糙，而且还出现皮下血管出血。这是由于他偏食，造成体内缺乏(    )

A．维生素A和维生素D

B．维生素A和维生素B 1

C．维生素D和维生素C

D．维生素A和维生素C

As he didn’t have much money, he had to ____ a second- hand computer for his work.

A．pick up

B．give up

C．look up

D．take up