You're going on a trip to a foreign country for a few weeks, and your roommate is helping you decide what to take with you. You aren't sure if you should take your notebook computer with you or not. You make a thoughtful face and say:
I'm trying to decide whether I should take my laptop.
Use this phrase when you are "in the middle" of making a decision – when you're thinking of the different possibilities. Here are a few more examples:
I'm trying to decide what to order.
Everyone's trying to decide where to go for drinks.
I'm trying to decide whether or not I should apply for this job I saw posted on my company's intranet.
"Whether" is similar to "if". In the example above, you can also say:
I'm trying to decide if I should take my laptop.
You might choose to use "whether" instead of "if" just because of the sound. "Whether I" sounds easier to pronounce than "if I".
In written English, you should follow "whether" with "...or not":
I'm trying to decide whether I should take my laptop or not.
You can also use "...or not" in spoken English, but you should put it right after "whether":
I'm trying to decide whether or not to take my laptop.
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