研究报告的“灵魂”是( )
A.摘要
B.材料
C.提纲
D.主题
参考答案:D
如果用一个平面去截一个几何体,所得任意截面都是圆,则这个几何体是( )。
In order to support the big family, he worked so hard that___________ he made himself ill.
A.occasionally
B.purposefully
C.normally
D.eventually