Verbs ending in -e simply add -d to form the past tense. This is the most straightforward regular rule.
Cornerstone is regular. It follows the -d Addition rule.
Use past time markers: "Yesterday, she cornerstoned to the store."
No. Use "did not cornerstone" (not "did not cornerstoned").
The verb cornerstone follows the standard English past tense conjugation rule. When forming the past tense, cornerstone becomes cornerstoned. This follows the -d Addition pattern, which is one of the most common conjugation rules in English.
Understanding why cornerstone becomes cornerstoned 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 cornerstoned 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 cornerstoned to the store." The past tense form does not change based on the subject — I cornerstoned, you cornerstoned, he/she cornerstoned, we cornerstoned, they cornerstoned.