Outside my office window there is a fire __________ on the right.
Some scientists believe that it won’t be long _______ robots are widely used in all walks of life.
Under no circumstances _______ the difficulties when they were on an expedition to the Antarctic.
In the city, I saw so grand a National Day celebration _______ I never dreamed of.
If only I _______ more confidence in the English speech contest held last week!
According to the school rules, no child _______ be allowed out of the school during the day, unless accompanied by an adult.