Answer : Birds fly in the sky, according to the supplied phrase. The Simple Present Tense has been used in this statement.
In this case, we may write this in every tenses as follows:
- Simple Past: Birds flew in the sky.
- Present Continuous: Birds are flying in the sky.
- Simple Future: Birds will fly in the sky.
- Past Continuous: Birds were flying in the sky.
- Present Perfect: Birds have flown in the sky.
- Future Continuous: Birds will be flying in the sky.
- Future Perfect: Birds will have flown in the sky.
- Past Perfect: Birds had flown in the sky.
- Past Perfect Continuous: Birds had been flying in the sky.
- Present Perfect Continuous: Birds have been flying in the sky.
- Future Perfect Continuous: Birds will have been flying in the sky.