QUES: acceptable (OPTIONS:
- unacceptable
- acceptable)
ANS: It was believed that the earth was round.

QUES: acceptable (OPTIONS:
- unacceptable
- acceptable)
ANS: The bed on which Tom slept was hard.

QUES: acceptable (OPTIONS:
- unacceptable
- acceptable)
ANS: There happened a serious accident yesterday.

QUES: acceptable (OPTIONS:
- unacceptable
- acceptable)
ANS:
I gave a birthday present to my brother.