微量元素（）补充过量可致恶心、呕吐、毛发脱落、指甲异常等。
A.锌
B.锰
C.硒
D.铁
参考答案：D
In relation to the contents of a contract, explain the following:
(a) suspensive conditions; (5 marks)
装盒中常选用分装法的是
A．少数前牙缺失B．活动矫治器C．护板D．全口义齿E．余留牙很多
