If unsure about ie or ei, when the seem of the vowel is as in brief /i:/, we spell it ie; but after the letter c, we spell it ei: … For instance, "apple" becomes "apples"; "tree" turns to "trees"; "reserve" variations to "publications"; "painting" becomes "paintings"; and "sign" modifications https://spellingrulesinhindi86318.angelinsblog.com/27747572/top-guidelines-of-spelling