职业卫生三级预防原则的第一级预防是（）（从根本上消除和控制职业病危害因素）。
参考答案：病因预防
He left home without saying a word, and _______ worries many people and is to be found out.
A．where he has gone
B．where did he go
C．which place has he gone
D．where has he gone
依据《食品卫生法》第37条对可疑食品应采取临时控制措施，控制期限为几天
A．5天
B．7天
C．10天
D．15天
E．20天
