Because he thinks it is good for her ____ (spend) more time with her friends.
已知等式x4+a1x3+a2x2+a3x+a4=x+14+b1x+13+b2x+12+b3x+1+b4定义映射f:a1,a2,a3,a4→b1,b2,b3,b4,则f4,3,2,1=( )
如图是一个等边三角形木框,甲虫P在边框AC上爬行(A,C端点除外),设甲虫P到另外两边的距离之和为d,等边三角形ABC的高为h,则d与h的大小关系是 ( )
自来水最好用盆装着在阳光下晒一、二天后,再用来养鱼.____