Spring is their estrus, the sound all time in night like crow blood is for beckoning their 'Mating objects'.

春天是它们的发情期，夜间啼血般地叫个不住，是召唤‘婚配对象’哩！

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Proper torquing avoids elastic separation of the mating parts under load and resists gradual loosening over time.

扭矩正确，就能防止配合部件在负荷作用下出现弹性分离，并防止部件在长期运转过程中逐渐松动。

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Sandhill cranes mate for life, and if it is their first mating season, the bonding begins around the time they get to Nebraska.

BBC: Nebraska��s awe-inspiring crane migration

The movie, directed by George Marshall, pairs Ladd and Lake for the third time, and their coolly enacted mating dance is something to savor.

WSJ: Dark Crimes: Film Noir Thrillers

Now, she added, the post-proposal time period is considered its own step in the mating process.

CNN: STORY HIGHLIGHTS