So this one is a little bit older penny.

这个硬币比较老旧。

And your cupcakes taste like old pennies.

你们这纸杯蛋糕太难吃了。

So these old pennies soon became so smooth that one could not tell " head" from " tail, " or indeed see any letters on the pennies at all.

所以， 这些老硬币很快就会磨得太光， 连正反面都看不出来， 便士上的字母更是磨得一个也看不见了。