As a Chinese saying goes, a mountain ______ be too high or an ocean too deep. Therefore, there is no end to our self-improvement.
___ is known to all, China will be an _____ and powerful country in 20 or 30 years’time.
I remember a ____ famous scientist said that we should believe in ourselves first of all.
I think you should complain, _____, of course, you are happy with the way things are.
Rescuers had to _____ the search because of worsening weather conditions.
—Are you sure Mike will help us if we are in trouble? — _____. He is a reliable friend.