To my surprise, he was lost in thought then and not ____ of my presence at all. 

In the history of Chinese revolution, Taierzhuang Battle was a ________ battle in which both sides suffered heavy losses.

A cough is usually nothing to worry about unless it lasts for ten days ___.

—How was Robert's cooking? —Oh, pretty good. I was quite _____.

 _________several times, but Mary still has no idea of how to do it properly.