3 sentences

1. 事已至此，奈何？

   shì yǐ zhì​cǐ, nài​hé?

   Things have come to this; what can be done?

   Source: Dong Chinese Dictionary

2. 事已至此，他怎能不后悔自己的决定？

   shì yǐ zhì cǐ, tā zěn néng bù hòu​huǐ zì​jǐ de jué​dìng?

   Now that things have come to this, how can he not regret his decision?

   Source: Dong Chinese Dictionary

3. 事已至此，你再怎么自责也于事无补。

   shì yǐ zhì cǐ, nǐ zài zěn​me zì​zé yě yú​shì​wú​bǔ.

   Now that things have come to this, no amount of self-blame will help.

   Source: Dong Chinese Dictionary