—I'd rather some water. It's also good for our health.
A:have
B:to have
C:had
D:having
长江流域洪涝灾害最集中、最严重的地区是( )
如图是电阻RA和RB两端电压与电流的U﹣I图象.如果将RA和RB串联起来,它们两端电压之比为____;如果将RA和RB并联起来,通过它们的电流之比为____.
关于中纬环流的叙述,正确的是( )