根据对患者人身造成的损害程度，医疗事故分为______
Suchperson_______youdescribeisrarenowadays.
Theboycomplained_______apaininhisstomach.
重写句子：NotuntilhecrossedthelineandfeltthetapesnapagainsthischestdidJohnsonknowhehadwontherace.(loosesentence)
Homingpigeonisusefulasa______carrierbecausewhentakenfromhome,itwillreturnatthefirstopportunity.
