6岁女童，喜食泥块，面色萎黄，血红蛋白92g/L，治疗应首选的药物是（）。
A.抗生素
B.葡萄糖
C.维生素类
D.铁剂
E.钙剂
参考答案：D
— Thomas didn't come to school for the meeting, did he?
— No. He ____. The meeting had been cancelled.[ ]
A. shouldn't have come
B. should not come
C. didn't need to come
D. wouldn't have come
上海盛绿等食品公司，向面粉中添加柠檬黄（混有铬酸铅，化学式为PbCrO4）制作“染色”馒头。食用“染色”馒头会对人体造成危害。已知铬酸铅中铅元素的化合价为+2价，则铬元素（Cr）的化合价为[ ]
A.+6
B.+4
C.+2
D.+1
