He has two sons. They are Jim and Tom. Jim is Tom's brother.
A:old
B:older
C:elder
D:young
已知角x的终边上一点坐标为sin5π6,cos5π6,则角x的最小值为( )
镍氢电池是近年开发出来的可充电电池,它可以取代会产生镉污染的镉镍电池.氢镍电池的总反应式是:12 H2+NiO(OH)=Ni(OH)2据此反应式判断,下列叙述中正确的是( )