Scientists use "hole" as a metaphor for the area in which ozone concentrations drop below the historical threshold of 220 Dobson Units.

科学家们用“空洞”一词表示臭氧浓度低于220个多布森单位（多布森单位是用来度量大气中臭氧柱尺度的单位。

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To change to a different unit, choose your preferred units from the drop-down menu on the right, as illustrated in Figure 10.

若要更改为不同的单位，请从右侧的下拉菜单中选择首选的单位，如图10所示。

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In September, while the industry overall suffered a 22% sales drop in a post-Cash for Clunkers hangover, Hyundai managed to increase its new-vehicle tally by 27% to 31, 511 units.

9月，当在后旧车换现金方面，工业销售额惨遭22%全面下跌时，现代却设法使自己的新车销量增加27%到31511辆。

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Suppose a player were to break his arm during the contest, a user can trade their units in that player, but the value of the units will drop if everyone tries to sell them at once, emulating a stock exchange.

FORBES: Scramble For Cutting Edge Fan Participation Continues

The Xbox 360 once again topped the NPD Group's hardware charts in July, claiming a near-majority 49 percent market share of consoles -- but the 203, 000 units sold were a steep drop from the 257, 000 units that traded hands in June, and a far cry from the glory days that would have given a victory more meaning.

ENGADGET: NPD: Xbox 360 ruled a steadily declining video game empire in July

We see a steep drop off in revenues and units near term, punctuated by a drop in subscriber adds, and an OS refresh that is largely ignored by carriers and consumers alike, driving RIM into a forced sale in 2013.

FORBES: Why RIM Won't Be Bought: There's Not Much There There