范文：
The past tense of the verb "smile" is "smiled." For example, when discussing an event that occurred in the past, one might say, "She smiled warmly at her friends when they entered the room."
常见问答知识清单：
1. What is the past tense of smile?
2. How do you form the past tense of smile?
3. Can you use smiled in a sentence?
4. What is the past participle of smile?
5. Is smile irregular in the past tense?
6. How do you conjugate smile in the past tense?
7. What is the difference between smiled and smiled at?
8. Can smiled be used as a past participle?
9. How do you use smiled in a passive voice sentence?
10. Is there a past tense form of smile that means to keep smiling?
详细解答：
1. What is the past tense of smile?
The past tense of "smile" is "smiled."
2. How do you form the past tense of smile?
The past tense of "smile" is formed by adding the suffix "ed" to the base form of the verb, which is "smile."
3. Can you use smiled in a sentence?
Yes, "smiled" can be used in a sentence like this: "He smiled when he received the good news."
4. What is the past participle of smile?
The past participle of "smile" is also "smiled."
5. Is smile irregular in the past tense?
No, "smile" is considered regular in the past tense. It follows the pattern of adding "ed" to form the past tense.
6. How do you conjugate smile in the past tense?
To conjugate "smile" in the past tense, you add "ed" to the base form: "smile" becomes "smiled."
7. What is the difference between smiled and smiled at?
"Smiled" is the past tense of the verb "smile." "Smiled at" is a phrasal verb that means to show a friendly or pleased expression by smiling at someone. For example, "She smiled at the child."
8. Can smiled be used as a past participle?
Yes, "smiled" can be used as a past participle, particularly in passive voice constructions. For example, "The picture was smiled at by everyone."
9. How do you use smiled in a passive voice sentence?
In a passive voice sentence, "smiled" can be used like this: "The girl was smiled at by the audience."
10. Is there a past tense form of smile that means to keep smiling?
There is no specific past tense form of "smile" that means "to keep smiling." However, you can express this idea by using a phrase like "continued to smile" or "remained smiling."
