Verb Tense and Mood

Make time relationships clear

Keep tense consistent when actions share a time frame; change tense when the time relationship changes. A shift is an error only when it is unjustified or confusing.

• Past perfect (had + past participle) marks an earlier past action when the order needs clarification: “The film had begun before we arrived.”
• Present perfect (has/have + past participle) connects a past action or period to the present: “She has worked here since June.”
• Future perfect (will have + past participle) marks completion before a future point.

Time words can make simple past sufficient, so do not add perfect tense mechanically.

Recognize justified shifts

“The article was published in 2020 and remains influential” shifts correctly from a completed event to a present condition. In reported speech, keep the meaning and time reference clear; backshifting is common after a past reporting verb, but a still-true general fact may remain present.

Worked example: “The laboratory opened in 2015 and serves the community today” shifts for a reason: the opening is complete, while the service continues. Changing serves to served would suggest that the service also ended and would alter the meaning.

Match mood to purpose

Statements/questions, directions and hypothetical conditions call for different forms. Their supporting names are indicative, imperative and subjunctive; prioritize selecting the correct form in context. Use the base form after demands (“They recommended that he revise”) and were in formal contrary-to-fact statements (“If I were ready”). Do not confuse a real possibility with a contrary condition.