[Q]: How does the sentence end?

James cannot make a copy of the book on that sheet because the 

[A]: sheet is shorter.


[Q]: How does the sentence end?

Christine needed help from Erin to make a sofa cover because 

[A]: Christine didn't own a sewing machine.


[Q]: How does the sentence end?

Steven dropped out of marathon training while Derrick trained harder. 

[A]:
Steven had already suffered a bad ACL injury.