This downward movement forces the valve to move downward off its seat so that it opens.

向下的运动使气门向下移动离开气门座，气门被打开。

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He quickly grasped a small tree By the side of the precipice and Began to move downward Bit By Bit.

他迅速抓住悬崖边上的一颗小树，一点一点向下移动。

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The law shows that, along with the static pre-load increasing, the dynamical bending strength of concrete would go up to a peak value and then move downward to the static strength.

计算结果显示，不同细观骨料模型具有相似的规律，即随预静载增大，混凝土动弯拉强度上升，至一定峰值后回归到静载强度。

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The sudden downward move caused stop orders for many stocks to be executed, leaving some shareholders with unanticipated losses or realized capital gains.

FORBES: Lessons From The Flash Crash

In more blunt terms, a downward move by domestic large-cap stocks now has an increased chance of dragging down emerging market stocks, REITs and commodities with it.

FORBES: Benefits From Asset Allocation Are Harder To Come By

These folks, for instance, divine that something called a "head-and-shoulders top" formation--a market high above two high points on either side--means that stocks are poised for a downward move.

FORBES: Uncharted territory