50到70的英文是：Fifty to seventy.

fifty： num.五十个人;五十岁;五十年代;编号为五十的东西五十;五十个。

seventy：num.七十;七十几;七十年代。

Around fifty people die of hunger every day in the camp.

集中营里每天大约有五十人饿死。

To look at him you'd never think he was nearly fifty.

看他的外表，谁也想不到他年近五十了。

He's ancient ─ he must be at least fifty!

他老得很了——肯定至少有五十岁！

They were planning to evacuate the seventy American officials still in the country

他们正计划转移仍滞留在该国的70名美国官员。

The ship could carry seventy passengers.

那艘船可以载客70名。