A:交通便利,经济发达的地区
B:科技人才密集、科研基础良好、自然条件适宜的地方
C:城市人口密集的地区
D:乡村人口稠密的地区
一个乘数是5,另一个乘数是9,积是( )
用所给词的适当形式填空
(1)He came back home early____(cook)supper for his son.
(2)What about____(play)football after class?
(3)Do you like____(Europe)modern music?
(4)The Smiths____(be)here in two minutes.
(5)We all know a Chinese soldier____(call)Lei Feng.
已知⊙O1与⊙O2内切,它们的半径分别为2和3,则这两圆的圆心距d满足( )