back up ring

基本解释

Ring up when you get back from your holidays.
你度假回来后请打个电话来。
When the O-ring has relaxed to grasp the shoulder protection, the bonnet assembly may be assembled into the body with the O-ring clinging to the back-up washer.
当放松O形环使其恢复原状，此时O形环就抓紧肩部保护，带着粘附着后部垫圈的O形环，阀帽组件可以组装进阀体内。
With the improvement of living and the strengthening of consumers self-realization, more and more self-symbol-product, such as CRBT(Color Ring Back Tone), well up in market.
生产力的提高、人们自我意识的加强，促使越来越多类似彩铃的自我符号性商品涌向市场。

Sometime between the engagement and the Christmas holidays they broke up, but got back together again just in time to ring in the New Year.
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