倍数句型：

　　1. The average income of the staff has been ______________(与去年相比增加了50%).
　　2. The size of the newly broadened square __________________(是以前的四倍大).
　　3. After the new technique was introduced,the factory_______________(2000年能生产的卡车是往年的两倍).
　　

　　答案：
　　1.increased by 50 percent compared with last year
　　2.is four times that of the previous one
　　3.produced twice as many trucks in 2000 as the year before