一般蛋白质不含的元素为()
A.碳、氢、氧
B.氮
C.磷
D.钾
E.硫
参考答案:D
解析:一般蛋白质不含钾,所以答案为D。
某加热装置的工作原理如图所示,两电阻丝的阻值相等。电源电压不变,它有高、中、低温档三个工作状态。当开关S1接b,S2断开时,它是处于 状态,此时电路功率为P1;当开关S1接a,S2闭合时,电路功率为P2,则P1∶P2= 。
---- Our holiday cost a lot of money.
---- Did it ? Well, that doesn’t matter_______ you enjoyed yourself.
A.as long as
B.unless
C.as soon as
D.though