Technically, back labor occurs when the fetus is in a posterior position, with its face up and the back of its head pressing against your sacrum, or the back of your pelvis.

从技术上来说，背阵痛发生在胎儿处于背对的位置，它的脸朝上而后脑勺紧靠你的骶骨或者骨盆后方。

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On the inhale expand the chest, lifting up and coming back to the starting position.

在吸气时扩展胸腔，举起回到开始体式。

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Ensure that you have a back-end conversion goal set up and the right analytics in place so that you can track which AD position is actually resulting in the most conversions.

要设定转换率目标，并进行正确的分析，以便追踪哪个广告位置真正能产生最大的转换。

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If anything happens to Kaepernick, back-up quarterback, Alex Smith, will be ready to regain the starting position.

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It was a two-hour debate, and each combatant had lots of data to back up his position.

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Smith, playing out of position on the wing, picked up the full-back's loose pass superbly on the run and had the pace to beat the cover and cross out wide, with Goode narrowly unable to add the conversion.

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