—Is Jack on duty today?—It ________ be him. It’s his turn tomorrow.
The professor, _______ the project, made a comment on the report.
Anyone who is in _______ of weapons without permission is considered law-breaking.
I wish I _______ play tennis with my brother this afternoon, but I have to study for a test.
As a teacher rich in experience, he knows how to _______ his ideas to these new students in a limited period of time.
His first book is of great use for our course. But his latest one is ______ worth reading.