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