(someone) is trying to decide (something)

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 (clause)

"Whether" is similar to "if". You can use them in the same way:

I'm trying to decide whether I should take my laptop.

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.

a laptop

"Laptops" are portable computers. They're also known as "notebook computers", but the word "laptop" is more common in casual spoken English.

Oh, did you get a new laptop?

Computers that are not portable are called "desktops".