Grammatically, certain phrases have similar functions and meanings, but one is truly idiomatic and the other is not. Here’s an example:
What we do this weekend depends on whether it is raining.
What we do this weekend depends on if it is raining.
Grammar nerds will point out that these two sentences have the same meaning, but the cool kids will know that the actual English idiom is “depends on whether.” Here, the cool kid gets the right answer on his GMAT, and the nerd is left out in the cold.
Here’s another one:
It’s been a long time since my high school days.
It’s been a long time ago my high school days.
This time, it’s the nerd who might point out the difference between “since” and “ago.” These words actually have different definitions. “Since” carries a thought from the past to the present, and “ago” carries a thought from the present to the past. In our example sentences, “since” is the appropriate choice, but we can alter the sentence slightly so that “ago” becomes appropriate:
My high school days were a long time ago.
Do you see what happened there? The past is now the subject rather than the object of the subject, and “ago” is the more appropriate choice. Another thing to note: “ago” uses simple past tense, and “since” always uses a perfect tense.
Then, there are certain turns of phrase that befuddle cool kid and nerd alike. See this one here:
Our club received more than 100 applications.
Our club received over 100 applications.
“More than” and “over” are frequently used interchangeably, but on the GMAT, you can’t make this mistake. “More than” is used to determine quantities, which means that it is the correct choice for this sentence. “Over” should only be used to make spacial comparisons (“over the rooftops”).
Non-native speakers of English have particular difficulty recognizing idioms. In order to really ace sentence correction, you’ve got to know your English idioms down pat. Manhattan Elite Prep has a special expertise in assisting non-native speakers of English ace the GMAT, with endless techniques for learning, identifying, and using idioms correctly.