Birthplace data are only the crudest indicator of actual migration paths.出生地信息只能非常粗略地显示实际移民过程。At the crudest level, prices provide an incentive for production.从最基本的层次来说, 价格刺激生产.At its crudest, talk of " reciprocity " can...

v.挤压出( extrude的过去式和过去分词 )，挤压成，突出，伸出...

v.（使某物）伸出，（使某物）突出( protrude的第三人称单数 )...