Breakdown of На рубашке появилась такая заметная складка, что мне пришлось достать утюг.
я
I
на
on
рубашка
the shirt
появиться
to appear
Questions & Answers about На рубашке появилась такая заметная складка, что мне пришлось достать утюг.
Why is it на рубашке and not в рубашке?
На рубашке means on the shirt — on its surface.
That fits складка, because a wrinkle/crease is thought of as something on the fabric.
- на рубашке = on the shirt
- в рубашке = in the shirt / inside the shirt
So in this sentence, на is the natural choice.
Also, рубашке is in the prepositional case because it follows на in a location meaning:
- рубашка → на рубашке
Why is it появилась?
Появилась is the past tense, feminine singular, perfective form of появиться.
It agrees with складка, which is feminine:
- складка появилась
Why perfective? Because the sentence talks about a wrinkle appearing as a completed event:
- a wrinkle showed up / formed
If you used the imperfective появлялась, it would sound more like:
- was appearing
- used to appear
- kept appearing
That is not the idea here. Here, one noticeable wrinkle appeared, and that led to a result.