A:H2SO4 NaCl Na2CO3 CaCl2
B:HCl NaOH CuSO4 MgSO4
C:Na2CO3 K2SO4 BaCl2 HCl
D:NaNO3 HCl CaCl2 KOH
She is our Chinese teacher. We like _________ lesson very much.
thirteen
一个梯形的上底长8cm,中位线长10cm,则其下底长为( )cm.
“圣诞老人,圣诞礼物,圣诞树……”与其相关的宗教是 ( )