The boss left the office angrily because of ______ his men said then.
Students show great interest in ______ Professor Edwards presents to them in his class.
—Are you going to the concert next week?—I’d like to, but I ______ an exam then.
—I didn’t know you play the piano. It sounds wonderful!—Thank you! I ______ it when I worked in UK.
We are going to the theater tomorrow ______ all the tickets are sold out.
Once ______, the book will surely attract readers’ attention since it is related to people’s health.