As a result, it is getting easier every day to tell these Siamese-twin cities apart.

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The easiest way to tell Test and limited-overs cricket apart is by looking at the players.

BBC: The difference between Test and limited-overs cricket

The two regimes are not easy to tell apart: the khaki-clad police are helmeted and heavily armed.

ECONOMIST: Bolivia: Clashes to come | The

There are about a dozen employees ambling about, some dressed so casually it's hard to tell the veterans apart from the college-student interns.

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Not only that, but while TiVo might have pushed the DVR into the mainstream, it hasn't meaningfully innovated since -- apart from HD output and the aforementioned streaming services, you'd be hard-pressed to tell a brand-new TiVo HD from an original unit by using it for five minutes.

ENGADGET: Ten years of TiVo: how far we haven't come

One concern raised by such contaminants is that chemically, radioactive and non-radioactivie iodides are too similar for the body to tell apart, thus raising the risk that radioactive iodides can accumulate and lead to further health risks.

FORBES: Researchers Develop Material to Remove Radioactive Contaminants From Drinking Water

The stock fell to an eight-year low after RIM announced that it would have no new BlackBerry models until late 2012 and, according to analysts, the problem with the current line-up is that there are so many models and features, nobody can clearly tell them apart.

FORBES: RIM Needs Courage to Escape Clutter and Confusion

Equally troubling are websites selling counterfeit merchandise, some so sophisticated they include anti-virus logos and the seal of the Better Business Bureau making them almost impossible to tell them apart from legitimate vendors.

NPR: SUPER BOWL WATCH: Beyonce, Avocados, Practice