—Where is Bob? I cannot find him anywhere.—He have been off long. I heard him make a call just now.
He loved his family, but seldom _______ spend much time with them.
A study shows that walking fast in your old age is a ______ that you will live a long life.
— Where _______ you put my dictionary? — I left it on your desk when you _______ to Tom.
Raising children is said to be a job _______ parents receive the least formal training.
_______ blood if you can and many lives will be saved.