Being injured in the leg made _______ impossible for him to walk his way home.
A large sum of money has been raised for the ______ of the poorly-educated children.
—I’m sorry I have failed again in the math exam. — _________ ? You’ve been working hard at the subject.
—I really don’t know how to thank you enough. —.
On our way to school, suddenly it began to rain, and we hurried to take______under a big tree.
I can still remember that it is since the 1990’s, _____ we began to use cell phones,_______ the number of mobile users has greatly increased.