What does Tony want to be when he grows up?
A:A doctor.
B:A player.
C:A policeman.
下列现象属于凝华的是( )
一根杠杆两端挂有等重的实心铜块和铁块,当它们都浸没在水中时,杠杆恰好平衡,现将铜块和铁块同时从水中取出,则杠杆将( )
与120°E经线构成经线圈的经线是( )