| singular | plural |
| Infinitive | | |
| constrain | |
| present simple | | |
| 1 | I constrain | we constrain |
| 2 | you constrain | you constrain |
| 3 | he/she/it constrains | they constrain |
| past simple | | |
| 1 | I constrained | we constrained |
| 2 | you constrained | you constrained |
| 3 | he/she/it constrained | they constrained |
| future simple | | |
| 1 | I will/shall constrain | we will/shall constrain |
| 2 | you will/shall constrain | you will/shall constrain |
| 3 | he/she/it will/shall constrain | they will/shall constrain |
| conditional simple | | |
| 1 | I would constrain | we would constrain |
| 2 | you would constrain | you would constrain |
| 3 | he/she/it would constrain | they would constrain |
| present continuous | | |
| 1 | I am constraining | we are constraining |
| 2 | you are constraining | you are constraining |
| 3 | he/she/it is constraining | they are constraining |
| past continuous | | |
| 1 | I was constraining | we were constraining |
| 2 | you were constraining | you were constraining |
| 3 | he/she/it was constraining | they were constraining |
| future continuous | | |
| 1 | I will be constraining | we will be constraining |
| 2 | you will be constraining | you will be constraining |
| 3 | he/she/it will be constraining | they will be constraining |
| conditional continuous | | |
| 1 | I would be constraining | we would be constraining |
| 2 | you would be constraining | you would be constraining |
| 3 | he/she/it would be constraining | they would be constraining |
| present perfect | | |
| 1 | I have constrained | we have constrained |
| 2 | you have constrained | you have constrained |
| 3 | he/she/it has constrained | they have constrained |
| past perfect | | |
| 1 | I had constrained | we had constrained |
| 2 | you had constrained | you had constrained |
| 3 | he/she/it had constrained | they had constrained |
| future perfect | | |
| 1 | I will have constrained | we will have constrained |
| 2 | you will have constrained | you will have constrained |
| 3 | he/she/it will have constrained | they will have constrained |
| conditional perfect | | |
| 1 | I would have constrained | we would have constrained |
| 2 | you would have constrained | you would have constrained |
| 3 | he/she/it would have constrained | they would have constrained |
