如果在一张以南极为中心的地图上画四个指向标,指向标的箭头应该[ ]
A、都指向图的上方
B、都指向图的下方
C、都指向图的中心
D、都指向图的四周
答案:D
I begged her not to tell anyone else, and she said she would ________.
A.keep her word
B.eat her words
C.leave word
D.in other words
下列哪些是肝包虫囊肿的特征表现
A.子囊密度高于母囊
B.囊内密度均匀,增强后明显强化
C.囊壁可呈弧形或蛋壳样钙化
D.母囊内出现子囊,数目不一
E.内囊可分离,悬浮于囊液中