Judging from his______ expression, this problem must be quite ______.
Living in a polluted environment, people may ___ easily.
With the ___ of Mr Liu, I made great progress in speaking English.
—Carolina didn’t invite us to her birthday party. —___? I don’t care.
Reforming the education system will be a long and difficult ___. In this course, people should make effort to throw the old one.
The manager demanded that all the work ___ ahead of time.