oblige|obliged

我很乐意帮忙。

I am happy to ___oblige.

在一些国家，年轻人必须服兵役一段时间。

In some countries, young people ___are ___obliged ___to serve in the military for a period.

经理非常乐意帮忙。

The manager was only too happy to ___oblige.