没有被动语态
settle down 的用法:
settle down定居(使)平静下来专心于(后接介词to)
(1)settle downto(doing)sth.开始认真做某事
settlein/into 适(新的家、工作、环境等)(2)settlementn.解决定居协议
settler n. 定居者移民者 
Wait until the children settle down before you start the lesson.等学生都静下来再开始上课。
①The noise outside stopped me from settling down todoing  my work.外面的噪音使我无法定下心来工作。
②After he returned to China,he married and settled  down in Beijing.他回到中国以后就结了婚,并在北京定居下来。
③With a lot of problems  to settle,I can't go out with you.有许多问题要解决,我不能与你一起外出。