Sanded or Sanded? How is it correct?
Quote from Rules-56 (Rules of Russian spelling and punctuation):
The word "polished" is derived from the verb "polish". It can be seen as a participle and as a verbal adjective. In both cases, you need to write two letters H: if this participle, then paragraph 62 applies; if it is a verbal adjective, then paragraph 63 should be applied.
See also Rosenthal 52, para. 2, note 2.
The adjective or participle polished is derived from the verb polish. In its composition, it is difficult to write double N. To explain where they come from, let's perform a morphemic analysis of this adjective. Its root turns out to be the morpheme SHLIF-: Grind-Grind. Next, the suffix OBA is highlighted from the verb Grind. And finally, the passive past participle is formed with the HH suffix if it is derived from a verb with this OBA suffix or the EBA suffix. Thus, as part of this adjective, you should write double H: GRINDED.
However, recently I have been observing how for other participles traditionally written with one H, a form with two HN appears in dictionaries, and the suffix of the participles H disappears from reference books altogether.
The adjective given by you in the question is a verb, that is, it is formed precisely from the verb "polish". And according to the rules of our Russian language, this kind of adjective yes plus still ending in the combination "ovanny" will be written with two letters "n". Our case is GRINDED.
This word should be written competently with a doubled "n", namely "polished", since its second part contains the combination "oval" and it does not fall under the list of exceptions that have one letter "n" with a similar ending.
In the spelling of verbal adjectives, there is a rule that states that in adjectives on -owned / -bathroom is written -NH-:
grind - thin sectionovan floor;
pamper - ballovan child;
uproot - crampsbathroom plot;
varnish - varnishoval shoes.
Exception from this rule are the words: forged, crumpled, crumpledwhich include -ow - / - in- is part of the root.
When choosing N and NN in verbal adjectives and participles, it is useful to know the following information:
In participles, NN is written in full form and N in short form: a painted picture - a picture is drawn.
In verbal adjectives (short and full), H and HH can be written, since when they are formed, the suffixes H / HH and EH / EHN are used: a) effective, made, trained and b) dyed, called, tricky.
A number of adjectives and participles make up a pair, the choice of N / NN is determined by the dependent word: painted fence - fence painted last year.
To facilitate the task of choosing N / NN, the rule of 4 signs is used, which makes it possible not to distinguish between participles and adjectives: NN is written if there is a prefix, a dependent word, when it is formed from a perfective verb (purchased) and if there is a suffix OBA / EVA: pickled, trained. This rule is formal, it has a number of exceptions, but nevertheless, in many cases it allows you to quickly solve the problem.
Forged, chewed, crumpled is no exception, here H is chosen according to the rule of 4 signs (no prefix, dependent words, image from a non-Soviet verb, no suffix ОВА / ЕВА, since ОВ / ЕВ is part of the root). But the words should be remembered, since they are consonant with the words pickled, trained.