Two records, two different time frames
1A student club runs a small tool library. Members can borrow rulers, brushes, and simple repair tools instead of buying new ones. The library opened in March. Jina joined the club in April and is still a member. She has known the library manager since April. Last Friday, she helped the manager move several boxes to a different room. That job ended before the building closed.
2The club keeps two kinds of records. One describes completed events: when a shelf arrived, who repaired a broken box, and which room the group used last year. The other describes the library's present situation. The club has owned a set of measuring tools for six months, and those tools are still available. It has also received several new brushes this week. The week is not over, so the number may still change.
3Jina notices that a long period does not always continue into the present. A former member worked at the library for two years but left last December. In contrast, the current manager has worked there for two years and still comes every Saturday. The words for two years appear in both descriptions. To understand the difference, Jina checks whether the person's connection with the library has ended. She now reads the time expression together with the rest of the record, rather than choosing a verb form from one familiar word.