A:3
B:±2
C:±3
D:7
I __________ a gift yesterday, but I didn't ________ it.
What did the boy do?
在农业生产上,2,4﹣D可用于麦田除草,其原理是( )
春秋时期,奴隶社会逐渐崩溃。它在政治上最突出的表现是( )