易燃化学试剂存放和使用的注意事项正确是()
A.要求单独存放于阴凉通风处
B.放在冰箱中时,要使用防爆冰箱
C.远离火源,绝对不能使用明火加热
D.以上都是
参考答案:D
Two groups of people are compared in the third study. They are people().
A.with less than5 hours of sleep a night and with 7 to 9 hours of sleep
B.who slept 4 hours a night and who slept 4 hours for 2 nights
C.with less than 4 hours of sleep a night and with 7 to 9 hours of sleep
D.with less than 5 hours of sleep a night and with 8 hours of sleep
水溶性维生素中最易于在体内储存的是()。
A.硫胺素
B.视黄醇
C.烟酸
D.叶酸
E.维生素B