Verbs ending in -e simply add -d to form the past tense. This is the most straightforward regular rule.
Caffeine is regular. It follows the -d Addition rule.
Use past time markers: "Yesterday, she caffeined to the store."
No. Use "did not caffeine" (not "did not caffeined").
The verb caffeine follows the standard English past tense conjugation rule. When forming the past tense, caffeine becomes caffeined. This follows the -d Addition pattern, which is one of the most common conjugation rules in English.
Understanding why caffeine becomes caffeined helps with spelling and pronunciation. Verbs ending in -e simply add -d to form the past tense. This is the most straightforward regular rule.
When using caffeined in writing, remember that it functions as a past tense verb and typically appears with time markers like yesterday, last week, or ago. For example: "Yesterday, she caffeined to the store." The past tense form does not change based on the subject — I caffeined, you caffeined, he/she caffeined, we caffeined, they caffeined.