1. The data that the researchers collected ____ crucial for their study.
2. Either the director or the actors ____ responsible for the success of the project.
3. Half of the cake ____ already been eaten by the children.
4. They will have been living in the city for five years by next summer.
5. He often plays the piano beautifully during family gatherings.
6. The students will complete the assignment on time if they stay focused.