| Presente (Present) "ascertain" | I | ascertain | |
| Presente continuo (Present Continuous) "ascertain" | I | am ascertaining | |
| Pasado simple (Simple past) "ascertain" | I | ascertained | |
| Pasado continuo (Past Continuous) "ascertain" | I | was ascertaining | |
| Presente perfecto (Present perfect) "ascertain" | I | have ascertained | |
| Presente perfecto continuo (Present perfect continuous) "ascertain" | I | have been ascertaining | |
| Pasado perfecto (Past perfect) "ascertain" | I | had ascertained | |
| Pasado perfecto continuo (Past perfect continuous) "ascertain" | I | had been ascertaining | |
| Futuro (Future) "ascertain" | I | will ascertain | |
| Futuro continuo (Future continuous) "ascertain" | I | will be ascertaining | |
| Futuro perfecto (Future perfect) "ascertain" | I | will have ascertained | |
| Futuro perfecto continuo (Future perfect continuous) "ascertain" | I | will have been ascertaining |