---Tell me something about your adventure in the rainforest, please.---We lost our way in the forest and ___ made matters worse was ___ night began to fall.
________ you happen to see Mary, would you please ask her to come here?
Everyone knows that _______ is dangerous to play with fire, but _______ is difficult is to prevent children from playing with fire.
Not until the early years of the 19th century ________ what heat was.
Tom kept quiet about the accident ________ lose his job.
A driver should __ the road when .