Who’s singing in the garden—It ________ be Tom. He always practices singing at this time.

Where did you find the professor who made the speech yesterday？—It was in the hall ______ the students often have a meeting.

It’s going to be some time _____ he sees his father again, _____ business has just been started in Switzerland

In front of our house ________ we used to swim.

My parents don’t mind what job I do ______ I am happy.[ ]