Some of our industrial products may well be said ________ advanced level.
Mr. Richard hasn’t got any time to play golf these days, because he is ______ in the research of bird language.
When the newspaper boy got to a blue door, __________, which frightened him away as fast as possible.
When the clock_________ twelve, all the lights went out.
The man pulled out a gold watch, ______ were made of small diamonds.
Though I am improving in my study, I still have a long way to go _____some of my classmates.