| Present "concentrate" | I | concentrate | |
| Present Continuous "concentrate" | I | am concentrating | |
| Simple past "concentrate" | I | concentrated | |
| Past Continuous "concentrate" | I | was concentrating | |
| Present perfect "concentrate" | I | have concentrated | |
| Present perfect continuous "concentrate" | I | have been concentrating | |
| Past perfect "concentrate" | I | had concentrated | |
| Past perfect continuous "concentrate" | I | had been concentrating | |
| Future "concentrate" | I | will concentrate | |
| Future continuous "concentrate" | I | will be concentrating | |
| Future perfect "concentrate" | I | will have concentrated | |
| Future perfect continuous "concentrate" | I | will have been concentrating |