统一市场single market
单相交流电动机single-phase AC motor【电】
单边突变结single-side abrupt junction【电子】
单面机架single side rack
单相三线制变压器single-phase three wire transformer
单极断路器single-pole circuit breaker
双眼单视binocular single vision
单刀单掷开关single-pole single-throw switch【电】