Learn English – Prefix and Suffix issue

I would use "Build answer sheet" or "Assemble answer sheet" or "Format answer sheet" or "Insert markers".

Also you have misspelled 'containing' in two places.

I would say a good rule of thumb is to look at the base form of the word.

If the base form of the word ends in a "y," then a noun form ending in "-ian" will generally be pronounced as two syllables. Intuitively, these words have a hard time losing that "ee" sound. For example:

• comedy => comedian
• custody => custodian
• history => historian
• library => librarian
• ovary => ovarian

If the base form of the word ends in a "c" or "g" (velar stops), then that originally hard "k" or "g" sound becomes "sh" or "j" respectively in front of the front vowel "i" of "-ian" and is pronounced as a single syllable (a form of elision). A similar transformation can happen for words that already end in "s" or "sh" sounds. For example:

• clinic => clinician
• cosmetic => cosmetician
• magic => magician
• theology => theologian
• Venice => Venetian

If the base form ends in most other consonants or vowels other than "y", then the "-ian" ending cannot be elided with the final consonant/vowel into a single syllable, and thus is pronounced as two syllables. In the case of final vowels, an infix "-n-" is generally used to separate the final vowel from the "-ian" ending. For example:

• guard => guardian
• pluto => plutonian

Finally, examples like "Asian" are in fact a slightly different construct, wherein the suffix "-n" is used to make an adjective. Words that would be confusing in this regard because they end in "-ian" include:

• Asia => Asian [one-syllable "-ian"]
• mammal => mammalian [two-syllable "-ian"] (here the root is really the Latin "mammalia" which is the term used for the Class of mammals)