这是可以理解的。

That's ___understandable.

考虑到情况，他们拒绝帮助是完全可以理解的。

Their refusal to help is completely ___understandable, considering the circumstances.

我猜他们不会允许我住在女性朋友家里，但这是可以理解的。

I guess they wouldn't give me permission to stay at a female friend's home, but that's ___understandable.