Q: Valid English sentence (grammatically) or not: It was then when we all went to bed.
OPTIONS:
- unacceptable
- acceptable

A: acceptable

Q: Valid English sentence (grammatically) or not: Gilgamesh perhaps should be leaving.
OPTIONS:
- unacceptable
- acceptable

A: acceptable

Q: Valid English sentence (grammatically) or not: Fred must both have been singing songs and have been drinking beer.
OPTIONS:
- unacceptable
- acceptable

A:
acceptable