Thisriverformsanatural_______betweenChinaandKorea.
Whenmakingmoderncameras,peoplebeganto_______plasticsformetal.
Many kinds of animals are believed to have _________from the earth
Withoutapropereducation,peoplecould_______allkindsofcrimes.
He works in our university as a visiting _______, not as a formal faculty member.