Why is the final consonant not doubled in past tense form of open and listen?

You're right to notice that the final consonant isn't doubled in "opened" and "listened." This is because the rules for doubling consonants in past tense forms are specific:

The Rule:

You double the final consonant only if:

1. The verb ends in a single consonant (not a vowel or a consonant blend like "sh", "ch", "th", etc.).

2. The last syllable is stressed.

3. The verb is followed by a vowel in the ending (usually "-ed").

Let's break down "open" and "listen":

* "Open": The last syllable is stressed (Open), but the final consonant "n" is followed by the vowel "e" in the past tense "opened." Therefore, the "n" isn't doubled.

* "Listen": The last syllable is stressed (listen), but the final consonant "n" is followed by the vowel "e" in the past tense "listened." Therefore, the "n" isn't doubled.

Examples where the consonant is doubled:

* "Stop": The last syllable is stressed (stop), the final consonant "p" is followed by a vowel in "stopped," and it's a single consonant. Therefore, the "p" is doubled.

* "Plan": The last syllable is stressed (plan), the final consonant "n" is followed by a vowel in "planned," and it's a single consonant. Therefore, the "n" is doubled.

Remember, these rules are about the structure of the word and how it is pronounced, not about the meaning of the word itself.