下列哪个时期生活在高氟区，可造成氟牙症发生
A．0～7岁B．8～15岁C．16～22岁D．23～30岁E．31岁以后
参考答案：A
两税法
I had great difficulty _____ the suitable food on the menu in that restaurant. [ ]
A. find
B. found
C. to find
D. finding
