1 Three of these exercises must be
done tomorrow.
2 The book you need can be found in any library.
3 The river can be crossed on a raft.
4 This mistake can be easily forgiven.
1. Mr. Bucket doesn't have to support his elderly parents.
2. They didn't have to turn to a private detective.
3. We won't have to admit that she is right.
4. She didn't have to study hard last semester.
1. Does Mr. Bucket have to support
his elderly parents?
2. Did they have to turn to a private detective?
3. Will we have to admit that she is right?
4. Did she have to study hard last semester?