I had just got up and was about to cook my breakfast,________the telephone rang loudly,but it hung up________I could answer it.
A:while;when
B:when;as
C:as;after
D:when;before
物质(括号内为杂质)
除杂试剂
分离方法
A
Fe( Cu )
HCl溶液
溶解、过滤、洗涤、烘干
B
CO2 ( CO )
O2
点燃
C
CuO( C )
——
隔绝空气加强热
D
FeCl2(CuC l 2)
Fe
溶解、过滤
—Do you have any problems if you ______ five minutes to read?—Well, I'm thinking about the new words. There are too many.