I'd like to ask about the rule:
Final -c changes into -ck before -ing, -ed, -er etc.
We change -ic to -ick before -ing and -ed
1. Before which suffixes we change c->ck? -ing, -ed, -er and others? (I suppose vowel suffixes?)
2. Do we change only the words ending in -ic or do we change all words ending in -c? (What to do when a word, for example, is ending in -ac?)