If we can keep _____ this speed, we'll arrive there in two or three hours.
Not until the early years of the 19th century______ what heat is.
_____ he realized it was too late to return home.
So little _____ agree on the plan that they could not settle their difference.
We were lucky enough, for no sooner _____ home _____ it rained.
____, he would have passed the exam.