How do you form the past tense of verbs ending in 'm' or 'n'?

To form the past tense of verbs ending in 'm' or 'n', we follow specific rules depending on the verb's ending sound.

1. Verbs ending in 'm':
When a verb ends in 'm', we usually replace the 'm' with 'ed' to form the past tense. For example:
- Dream becomes dreamed: "I dreamed about my vacation last night."
- Swim becomes swam: "She swam across the lake."

However, there are a few exceptions to this rule. Verbs that end in 'm' but have a vowel before the 'm' do not change in the past tense. For example:
- Beam remains beam: "The sunlight beamed through the window."
- Dream remains dream: "He dreamt of becoming a pilot."

2. Verbs ending in 'n':
When a verb ends in 'n', we also typically add 'ed' to form the past tense. For example:
- Open becomes opened: "She opened the door and entered the room."
- Listen becomes listened: "They listened to their favorite song."

Similarly to verbs ending in 'm', there are exceptions for verbs that end in 'n' but have a vowel before the 'n'. These verbs do not change in the past tense. For example:
- Burn remains burn: "The fire burned brightly."
- Learn remains learn: "He learned how to play the guitar."

It is important to note that irregular verbs, which do not follow regular patterns, may have different forms in the past tense. Therefore, it is necessary to consult a list of irregular verbs to determine their past tense forms.

In summary, to form the past tense of verbs ending in 'm' or 'n', we usually replace the 'm' with 'ed' or add 'ed' to the verb. However, there are exceptions for verbs with a vowel before the 'm' or 'n', as they do not change in the past tense.