Tense flexibility in reported speech

General statements are often reported in the Present Simple: The tutor explained that a triangle has three sides. A past form is also possible in such a report; it does not turn a triangle into a different shape.

To emphasise that a statement remains valid now, choose a present viewpoint. If you are simply reproducing the content of a past lecture, backshift can also be natural. A particular task may request a specific viewpoint, but that is an exercise constraint rather than a universal judgement on the alternative form.

A short interval after the conversation often gives a reason to retain a present form: the state, process, or result is still relevant. However, the word just does not itself prohibit backshift.

Preserve aspect as well: is checking presents a process, while has checked presents a completed check with a current result. Do not replace a form merely to avoid backshift if doing so changes an unfinished action into a completed one.

Even something heard a moment ago may no longer match the situation. A change of state must be explained explicitly: the facts, not the number of minutes, create the difference.

An unshifted verb does not require every other word to remain unchanged. Pronouns, today, tomorrow, here, and this must identify the correct people, day, and place from the reporter's viewpoint.

If the day or location is the same, tomorrow or here may remain even beside a backshifted verb. If the day or location has changed, a specific date or place name is often clearer than mechanically using that day or there.

When reporting will, would expresses the future from the viewpoint of a past conversation. The event may still lie ahead now, may already have happened, or may not have happened. The form alone does not report the outcome.

Will can be retained when a prediction, promise, or planned event remains current and future at the time of reporting. If you report an old plan after its scheduled date, do not present it as a new future event from your own viewpoint.

The Past Simple can often be retained if the time relationships are already clear: She said the power failed during the storm. The Past Perfect can additionally show that the event preceded the conversation: She said the power had failed during the storm.

The Past Perfect does not acquire another had. Likewise, could, would, should, and might remain unchanged in many ordinary reports. Do not mechanically add have + V3 (the past participle, such as finished or gone): this may create a different meaning, such as an assessment of an unfulfilled obligation.

In a longer report, choose forms for each time relationship. A general property can remain in the present alongside a completed past episode.

A report tells us what someone said. Even a present-tense form does not independently prove that the content is true or that you have personally checked it. You can report a current claim and mark uncertainty separately.

Past forms are not automatic signals of distrust either. To distinguish a report from your own knowledge, say so explicitly: I haven't checked, I don't know whether that's still the case, or but the latest figures show something else.

A practical sequence is to establish when the original words were spoken, identify what is known now, preserve the participants and time relationships, and add clarification if needed. Do not make one tense carry every message at once.