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