简单填空如下：
1.the_properties_______of the soil influence the growth of the plants.
2.small__amounts_______of land were used for keeping animals.
3.the son will follow his father's example and,__similarly______,the daughter will model
herself on her mother.
4.sailors use a(n)_compass_______to know in which direction their ship is headed.
5.the gas was_escaping_____from a small hole in the pipe.
6.the appearance of strange circles in fields of corn has__puzzled_____many people.
7.the job __offers_______plenty of opportunity for travel.
8.she stayed in the house for a few weeks ,but when she went,she left no_trace_____of having been there.
9.this__theory______helps to explain how animals communicate with each other.
10.i __normally_______go to bed early,but i stayed up late last night.
