The clothes need , but you do that by yourselves.
A:washing; needn't
B:washing; needn't to
C:to wash; don't need
D:to wash; don't need to
如图所示的转化关系中,A、C为常见的气体,B常温下是一种液体,D为黑色固体.
意大利科学家托里拆利首先测定了____ 的值;丹麦物理学家奥斯特发现____ 周围存在磁场;一根条形磁铁的____ 磁性最强(选填“两端”或“中间”).