Present perfect or past simple?
Both tenses talk about the past, but they do different jobs. We use the present perfect for past actions that are connected to now — a result, an experience, or news that still matters. We use the past simple for finished actions at a definite time in the past.
Aviation news is full of both. When easyJet and Rolls-Royce announced that they have run a jet engine on pure hydrogen for a full flight cycle, the present perfect signalled fresh, relevant news; when reporters described what the team did back in 2022, they switched to the past simple.
The two forms
| Tense | Form |
|---|---|
| Present perfect | have / has + past participle |
| Past simple | verb + -ed (or irregular form) |
When we use each one
Use the present perfect when the time is not stated, or when the result is what counts:
- Rolls-Royce has tested the Pearl 15 engine on 100% hydrogen.
- The team has reached full takeoff thrust for the first time.
Use the past simple when you give a finished time:
- In 2022, the partners ran a smaller AE2100 engine on green hydrogen.
- The test took place at NASA’s Stennis Space Center last month.
Watch the time markers
The words around the verb usually tell you which tense to choose. Already, just, yet, ever, since and for point to the present perfect. A finished time marker — in 2022, last April, yesterday, three years ago — forces the past simple. You cannot say “has tested in 2022“; once a finished time appears, switch to “tested in 2022“.
Gap-fill: inside the hydrogen test
Put each verb in brackets into the present perfect or the past simple.
- easyJet and Rolls-Royce __________ (complete) a full hydrogen test, and the result is making headlines today.
- In late April, the Pearl 15 engine __________ (reach) full takeoff thrust.
- This __________ (not / be) the first attempt; in 2022 the partners __________ (run) a smaller engine on hydrogen.
- Engineers __________ (test) fault scenarios during last month’s trial.
- The companies __________ (not / announce) a date for passenger flights so far.
Want to drill this tense on its own? Work through our dedicated present-perfect practice for more aviation examples.