列举不少于三类食品中存在的化学危害
参考答案：
重金属；天然毒素；农药残留超标；食品添加剂的过量添加；来自容器和包装材料的化学危害
女，36岁，超声心动图提示：二尖瓣关闭不全，体检时最可能发现的杂音是（）。
A.心尖区递增递减型收缩期杂音
B.心尖区递增型收缩期杂音
C.心尖区一贯型收缩期杂音
D.心尖区递减型收缩期杂音
E.心尖区连续型收缩期杂音
Why did regionalism become so popular in the U.S. during the Great Depression
A．Because the paintings sold very well.
B．Because it helped strengthen people’s faith in their country.
C．Because people liked to live in the country at that time.
D．Because it helped recover the economy.
