"Wearing dress shoes is uncomfortable."

Translation: 구두를 신는 것은 불편해.

[monochromm]

Why sometimes do we use 것은 and sometimes 것이?

[rimokon]

Overall, using 이/가 indicates that you found something out by yourself, by experience (eg. you are wearing these dress shoes right now and you are feeling uncomfortable).

은/는 on the other hand provides the feeling of comparing (when used specially for comparing there should be an another sentence to have enough context. Here, as additional information it could be: "my old sneakers are so comfortable").

But hey, don't worry about that at the beginnig - I heard that Koreans write their scientific works about the differences between those particles :)
So you can basically use 이/가 and 은/는 interchangeably.

[tessabanessa]

I was told you just have to get used to when to use which and that there isnt a clear rule.

[SydneyHopp2]

Is using 입는 instead of 신는 wrong? If so, what's the difference between the two?

[the_crait]

One is wearing something on your feet and one is wearing on your body.

[compcube]

I believe 신는 is used for things worn on the feet.

[4lbyeZMy]

these gerunds lesson is the hardest. It take me 30 minutes to complete a lesson

[spawn6000]

Saying 안 편해 is not accepted in place of 불편해? Why is that? Isn't it interchangeable?

[LoreGuKi]

Is using 쓰는 instead of 신는 also incorrect? Or could I use that aswell?

[AmandaStok10]

You don't really use the shoes, soo I would think that it would be incorrect.

[luisalim2126]

What does 것은/것이 means?