I am writing to express my _______ for the safety of children travelling on school buses, especially those on high-risk and highway-speed routes.
It is said that his carelessness ____ the terrible accident.
Tom as well as his friends ____ to visit our school soon after they arrive in Changsha.
By the time you ____ in, I ____ two letters.
To ____ your dream of becoming a scientist, you must work hard from now on.
I ____ go to bed ____ the telephone rang.