先天性聋哑是由常染色体隐性遗传基因控制的遗传病,双亲表现型正常,生了一个患该病的孩子,患该病的可能性[ ]
A.100%
B.75%
C.50%
D.25%
答案:D
It is said that Wang Feng’s new CD will ________ next month.
A.come up
B.come along
C.come over
D.come out
如右图所示的稳恒电路中, R1=1Ω,R2=2Ω,R3=3Ω那么通过电阻R1、R2、R3的电流强度之比I1:I2:I3为 ( )
A.1:2:3
B.3:2:1
C.2:1:3
D.3:1:2