I bought some CDs for my friends yesterday, and they ________ me $40. [ ]

A. spent

B. paid

C. cost

D. took

紫外线照射剂量为3～5MED，照射后4～6h出现明显红斑反应，2～3日消退，此为紫外线剂量分级中的几级

A．0级(亚红魔量)

B．Ⅰ级红斑量(弱红斑量)

C．Ⅱ级红斑量(中红斑量)

D．Ⅲ级红斑量(强红斑量)

E．Ⅳ级红斑量(超红斑量)