A:KNO3
B:CO(NH2)2
C:Ca(H2PO4)2
D:(NH4)2SO4
在水循环环节中,受人类活动影响最大的水循环环节是
如图:△ABC的周长为30cm,把△ABC的边AC对折,使顶点C和点A重合,折痕交BC边于点D,交AC边与点E,连接AD,若AE=4cm,则△ABD的周长是( )
—It's said the Nanjing Airport light rail_________ into service in two months.— That's great! It will be fast to go to the airport.