The definition is the same:
nplurals=3; plural=(n%10==1 && n%100!=11 ? 0 : n%10>=2 && n%10<=4 && (n%100<10 || n%100>=20) ? 1 : 2);
I have posted a link to the po file of version 2.9.2 above.
As you know, in English, plural form is much simpler. You have one string for singular, and all plurals are with an "s" at the end. Because of that, you don't need %s in singular form for English. But then again, in some plural strings you still have %s in singular, for example:
msgid "%s page not updated, somebody is editing it."
msgid_plural "%s pages not updated, somebody is editing them."
msgstr "%s stranica nije ažurirana, neko je uređuje."
msgstr "%s stranice nisu ažurirane, neko ih uređuje."
msgstr "%s stranica nije ažurirano, neko ih uređuje."
I checked my assumption stated above that without %s numbers 1,21,31 won't be displayed and it is correct.
I have used this string for testing:
msgid "Page moved to the trash."
msgid_plural "%s pages moved to the trash."
msgstr "%s stranica je premještena u smeće."
msgstr "%s stranice su premještene u smeće"
msgstr "%s stranica je premješteno u smeće"
Here are the screen shots.
21 pages deleted (without %s in form 0), there is no number of deleted pages in the yellow warning:
21 pages deleted (with %s in form 0), everything fine in yellow warning:
4 pages deleted (form 1):
7 pages deleted (form 2):
You should add %s in singular for strings like this just like in example with "page not updated" at the top of this message. No harm done to English or any other language and you will correct the error for all languages that are using plural form similar to mine.