— What do you think of Mary’s dress?

— I think it still looks quite fashionable on her           it is a style of many years ago.

A．though

B．unless

C．until

D．because

以初速度v₀竖直上抛一个物体，不计空气阻力，物体升高到某一高度时，其重力势能恰好是动能的2倍，则此高度为[ ]

A．

B．

C．

D．