The past tense is used for things that have already happened. He was sticky. The present tense is used when something is happening now or when something happens regularly. He is sticky.
The usual practice is to have the present tense express a current event while the past tense indicates the past. But there is a dramatic situation the present tense can state a past occurrence too.
For example, if you were writing a persuasive speech you may swap from the past tense to the present tense to the future tense to force your listeners to think about taking action: We have slowly ...
Unlike with participles, Latin has a full set of infinitives, that is, all six which are possible, encompassing both voices (active/passive) and all three tenses (past/present/future). Out of these, ...
UCSF abruptly canceled a two-day anti-racism class for doctors and nurses that was to be taught in February by a consultant who was targeted by right-wing groups that called his provocative content ...