Evidence means something that is used to determine the truth of a claim. Since evidence in reality is more often than not a discrete and quantifiable object, such as a statement, document, or material object, many students understandably say "an evidence" or "evidences." However, evidence is not a countable noun in the English language. In other words, you should not put "an" before evidence, or pluralize the word. Take a look at the following examples: - How much evidence does the government need before trying something new in the troubled realm of public education? Should there be airtight proof that a pioneering program works before we commit federal money to it — or is it sometimes worth investing in promising but unproven innovations? (New York Times Opinion, August 19, 2010): Notice how the author said "much evidence" instead of "many evidences."
- "We're announcing the discovery of two Saturn-size planets, which we're calling Kepler 9B and Kepler 9C," Holman said. And there's evidence of a third planet, he said — a much smaller one. Its diameter appears to be just 50 percent larger than Earth's. "If it is confirmed, it would have a radius of about 1.5 times the radius of Earth." Holman's discovery, in fact, is an early scientific harvest from NASA's new planet-finding machine — a telescope called Kepler. (NPR news, August 27, 2010): Note that the author said "there's evidence," not "there's an evidence"
The same rule applies to research. Although the word reminds people of a book or a report on a particular topic, making many people say "a research" or "researches," but this is incorrect. If you want to pluralize research or put an "a" before it, you should say "a study" or "studies" instead. Take a look at the following examples: - U.S. scientists reacted with dismay to Monday's decision by a U.S. judge to halt any expansion of stem cell research using federal funds..."It's an enormous impact, and it hurts more now trying to stop the additional research that's been going on [since the Obama order]," said Paul Sanberg, a stem cell expert and director of the University of South Florida Center for Aging and Brain Repair in Tampa. "Fortunately," he added, "there's still a lot of research on non-embryonic stem cells that is showing a lot of promise and going into clinical trials." (Business Week, August 25, 2010): Notice how the author did not say "stem cell researches" to refer to the research as a whole. Also note that he did not say "there are still a lot of researches."
- Motor vehicle accidents don't just impact the people involved, they also impact the economy, to the tune of just under $100 billion for medical care and injury-related productivity losses in the United States each year, according to a study released by the Centers for Disease Control and Prevention on Wednesday. (CNN, August 25, 2010): Unlike research, study is a countable noun. So you need "a" for a singular study.
- The governor can point to several studies that found little difference in binge drinking, alcohol-related fatalities or drunken-driving deaths between the 18 states that retain some control over the sale of alcohol and the other 32 states and the District, which do not. But McDonnell did not acknowledge other studies, completed by researchers across the country, that found public health differences between the two situations. (Washington Post, August 28, 2010): Again, study is a countable noun, so you can pluralize it with -es.
