1·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！
2·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。