短文填空。 make  allow  get quick  know  rain  keep  real We often hear people say 'It's __ 1 __ Cats and Dogs'. But do Cats and Dogs __ 2 __ rain? Of course not. It's an old saying. It means:  it is raining __3__ . Well, this saying came from old days in old England. People had hay (干草) roofs on their houses. The cats and dogs weren't __ 4 __ in the house in those days, so they, the dogs and cats, would__ 5 __ a warm place to sleep within the hay roof. The heat from the fire inside __ 6 __ the roof warm in winter and the night air made the hay __ 7 __ in summer. All in all, the roof was a nice place for an animal to sleep. But when it  rained heavily, the roofs __ 8 __ slippery. These animals would __ 9 __ drop down from the roofs to find a drier place. So, when it really rains heavily, we say it is raining cats and dogs. Now do you __ 10 __'It's raining Cats and Dogs'?