黄酮类化合物的首选显色剂是()
A.铝盐
B.锆盐
C.三氯化铁
D.盐酸-镁粉
E.四氢硼钠
参考答案:D
— Paul, could you please _____ the TV? It's too noisy.
— Sorry, I'll do it right now.[ ]
A. turn up
B. turn down
C. turning up
D. turning down
餐饮服务从业人员应每年进行()检查。