支配股四头肌、长收肌、短收肌和大收肌的脊神经是()
A.L1
B.L2
C.L3
D.L4
E.L5
参考答案:C
如图所示为一种家庭甩高效电膜式电暖炉的电路图,图中电暖炉选择开关S处于断开状态,电暖炉有左、右两个完全相同的发热电阻,每个发热电阻正常工作时的功率为550W.
(1)求每个发热电阻的阻值.
(2)选择开关S与哪两个触点接触时只有左发热电阻工作?
(3)若选择开关S与“2、3”两个触点接触,猜想此时电暖炉正常工作的功率大小.说出你猜想的依据.
I am too busy now. If I____ free, I ____to the cinema with you.
A.am; will go
B.am; would go
C.were; would go
D.was; was going