One factor contributing to the two-party system in the United States is the single-member districtsystem of electing Representatives.
导致美国两党制的一个原因是，每个国会议员选区只能选出一名代表。
2
Tip of series pipelines machines, the same applies to water quality sub-districtsystem, or even large cities different kinds of water pipe network system water groups to achieve effects.
同样蝶佳系列管线机更适用于小区分质供水体系，甚至是城市大型管网分质供水体系，实现群体供水之功效。
3
The road improvements and accompanying maintenance system had helped make the district centre accessible throughout the year.