. Everyone knows that _______ is dangerous to play with fire, but _______ is difficult is to prevent children from playing with fire.
37.After _______ the area for three hours, the police found the truck near a river.
36. Pakistan does not _____ the possibility of a war starting with India, but promises to do everything it can to reduce tensions (紧张).
35. The ______ bodies _______ the world ______ mummies.
34. The old lady has two daughters, _______ are famous actresses.
33. We were to go out for a walk ________ it began to rain.