| sg1st | sg2nd | sg3rd | pl1st | pl2nd | pl3rd | |
|---|---|---|---|---|---|---|
| Simple present | challenge | challenge | challenges | challenge | challenge | challenge |
| Present continuous | am challenging | are challenging | is challenging | are challenging | are challenging | are challenging |
| Simple past | challenged | challenged | challenged | challenged | challenged | challenged |
| Past continuous | was challenging | were challenging | was challenging | were challenging | were challenging | were challenging |
| Simple future | will challenge | will challenge | will challenge | will challenge | will challenge | will challenge |
| Future continuous | will be challenging | will be challenging | will be challenging | will be challenging | will be challenging | will be challenging |
| Present perfect | have challenged | have challenged | has challenged | have challenged | have challenged | have challenged |
| Present perfect continuous | have been challenging | have been challenging | has been challenging | have been challenging | have been challenging | have been challenging |
| Past perfect | had challenged | had challenged | had challenged | had challenged | had challenged | had challenged |
| Past perfect continuous | had been challenging | had been challenging | had been challenging | had been challenging | had been challenging | had been challenging |
| Future perfect | will have challenged | will have challenged | will have challenged | will have challenged | will have challenged | will have challenged |
| Future perfect continuous | will have been challenging | will have been challenging | will have been challenging | will have been challenging | will have been challenging | will have been challenging |
| sg1st | sg2nd | sg3rd | pl1st | pl2nd | pl3rd | |
|---|---|---|---|---|---|---|
| Simple present | don't challenge | don't challenge | doesn't challenge | don't challenge | don't challenge | don't challenge |
| Present continuous | am not challenging | are not challenging | is not challenging | are not challenging | are not challenging | are not challenging |
| Simple past | didn't challenge | didn't challenge | didn't challenge | didn't challenge | didn't challenge | didn't challenge |
| Past continuous | was not challenging | were not challenging | was not challenging | were not challenging | were not challenging | were not challenging |
| Simple future | won't challenge | won't challenge | won't challenge | won't challenge | won't challenge | won't challenge |
| Future continuous | will not be challenging | will not be challenging | will not be challenging | will not be challenging | will not be challenging | will not be challenging |
| Present perfect | have not challenged | have not challenged | has not challenged | have not challenged | have not challenged | have not challenged |
| Present perfect continuous | have not been challenging | have not been challenging | has not been challenging | have not been challenging | have not been challenging | have not been challenging |
| Past perfect | had not challenged | had not challenged | had not challenged | had not challenged | had not challenged | had not challenged |
| Past perfect continuous | had not been challenging | had not been challenging | had not been challenging | had not been challenging | had not been challenging | had not been challenging |
| Future perfect | will not have challenged | will not have challenged | will not have challenged | will not have challenged | will not have challenged | will not have challenged |
| Future perfect continuous | will not have been challenging | will not have been challenging | will not have been challenging | will not have been challenging | will not have been challenging | will not have been challenging |