"That pair of pants is too big!"

Translation: 那条裤子太大了！

[EuclaseW]

shouldn't 双 also work instead of 条

[NasuSamaruk0]

No, 双 actually refers to "unit type that naturally comes in pair", whereas 条 refers to "thin objects". For instance,

• 一双靴子: A pair of shoes
• 一条裤子: A pair of jeans

If we were to express the following...

一双裤子

then we are actually expressing that as "two pairs of jeans". Even though we can think of "jeans" as "two trouser legs", that doesn't happen in Chinese.

[whsndstalb]

If I got a dollar for every time I neglected the word and swapped "that" and "this i'd be able to buy the entire world

[Ant.H]

They mean "pants" as in "trousers" here, not underwear...

It would make more sense to use the version that means the same in both US and UK English!