You always sleep______the TV set______. [ ]
A.with, on
B.on, with
C.with, off
答案:A
A.ω0<ω,悬绳上端的电势高于下端的电势
B.ω0<ω,悬绳上端的电势低于下端的电势
C.ω0>ω,悬绳上端的电势高于下端的电势
D.ω0>ω,悬绳上端的电势低于下端的电势