“以某种速度”用英语怎么说?用什么介词?
问题描述：
“以某种速度”用英语怎么说?用什么介词?
Until midday,Mary's letter 空白 reached me.
A.being dated April 1 B.dating April 1
C.to date April 1 D.dated April 1
空白处应选什么，date的用法是？
答
at the speed of