5的倒数是 ( )
A:5
B:15
C:-15
D:-5
下列现象,属于共生的是( )
春季植树时,移栽的树苗常剪去一些枝叶,以提高成活率.其原因是减少枝叶可以( )
—In fact, last month's lecture is a_________. Since then, he's changed a lot.