单项选择题
Prices of daily goods（）through a computer can be lower than store prices.
A.are boughtB.boughtC.been boughtD.buying
单项选择题 That was another example of（）experience.
单项选择题 Three-fifths of the cattle（）sold abroad in the city.
单项选择题 He stepped into the dark cave，（）high above his head．
