A:making; would study
B:to make; was studying
C:to make; had studied
D:making; had been studying
由三条线段组成的图形叫做三角形。
2011年1月,怀宁县部分儿童血铅超标事件,倍受社会各界关注。铅元素相关信息如图所示。下列说法中,不正确的是( )