Let's learn to use the problem we are facinga stepping-stone to future success.
This is the third time I _______ Beijing. The second time I ______ here was on Christmas Day last year.
Computers can do a lot of things nowadays, but _____ more still need to be done by man.
Lectures were _____ so students could be more focused on their study for the finals.
He _____ on the bench, with his head down and his eyes _____ on the ground.
Every year, millions of people visit the Palace Museum, and many of __ are foreigners.