Sam _______ some knowledge of the computer just by watching others working on it. [ ]

A. brought up

B. looked up  

C. picked up

D. set up

在烹调蔬菜时，下列哪种做法易使水溶性维生素遭破坏（）

A.尽量保持植株完整

B.先洗后切

C.急火快炒

D.适量加些醋

E.下锅前用冷水浸泡，开水烫，挤去汁液