The report examines teaching methods _______in the classroom.

By _____ coincidence, oil paints were developed at thetime when ____technique of perspective was used.

I wasn’t blaming anyone: I ________ saiderrors like this could be avoided.

I don’t know how to deal with my family problem. Can you give me some_______

When I wanted to express my thanks to him，words ___ me. I just held his hands firmly and choked.