—She is cooking.
A:What
B:When
C:How
如图所示,电路两端的电压U保持不变,电阻R1,R2,R3消耗的电功率一样大,电阻之比R1:R2:R3是( )
中国古代很早就设有史官,老子就是著名的史官,而司马迁则是汉武帝时代的专职史官“太史令”。史官的设立表明 ( )
Susan _____ her friend's invitation because of an important meeting.
某正常动物细胞内Na+浓度低,K+浓度高.细胞内积累K+和排出Na+的运输方式是( )