Placeholders
Software strings may contain placeholders. These are replaced with text when the program runs.

For example:

%d - replaced with an integer
%s - replaced with a text
%f - replaced with a real number
%c - replaced with a single character

If "Put %d in the %s" is translated "%s 에 %d 를 넣으십시오"; that is if the order of %d and %s is reversed, the application cannot be built because the program expects a number in the first placeholder and text in the second placeholder. Consequently, it is very important to keep the order of the placeholders.

In the aforementioned example, it is easy to see that the order has been changed. In the following example, where "Put %s in the %s" is translated as "%s 에 %s 를 넣으십시오", it is difficult to spot.

The order seems to be correct. However, semantically it is not.

For example, if the first %s is replaced with "orange" and the second %s is replaced with "bag". Then the translation will yield:

오렌지에 가방을 넣으십시오

The translation should read as follows:

%s 를 %s 에 넣으십시오

where you have:

오렌지를 가방에 넣으십시오