One of the most complex spelling in the Russian language is an unstressed alternating vowel in the root. For example, the words "plants", "growth", "grown" and "grown" are cognate, but are spelled differently. What determines the choice of "a" or "o" in the roots of "rust", "growth" and "growth"?
Spelling Type
Unstressed vowels are fundamentally of three types: verifiable, unverifiable, and alternating.
Faced with an unstressed verifiable vowel in the root, it is enough to choose a verification word in which this letter will be stressed. For unverifiable, such words are not selected, so the correct spelling can only be learned. Alternating cases are especially important to remember, as an attempt to identify a vowel with the help of cognates can lead to an incorrect result.
This type refers to the spelling in the roots of “rust”, “growth” and “growth”.
The rule
The correct vowel can be selected based on the type of root: the letter "a" is written in front of "st" and "u", and "o" is placed in front of "c": to germinate, overgrow, grow, grow, overgrown, overgrown.
Naturally, in the roots of “rust” and “growth” under stress, you must write the vowel that is heard, as, for example, in the word “growth”.
Exceptions
In the case of the “root” root, the rule is always true, and there are exceptions for the “root” and “root” roots.
In a few words with the root "growth", always spelled "o": sprout, usurer, Rostov, Rostislav, for growth. All words formed from data are also written through an “o”.
For example, "usury" is formed from the "usurer" using the suffix "est", therefore the root vowel is "o". The noun "sprout" is obtained by adding the suffix "ek" to "sprout", therefore, in this case, we write "o".
The exception with the root of "races" is the word "industry" and all derivatives of it. For example, the adjective "intersectoral", formed by the prefix-suffix way.
Thus, for the correct choice of a vowel in the roots of “rust” and “growth”, it is enough to remember a simple rule and exclusion words.