In weeks of 7 days, three months can be 12 weeks and 5 or 6 days, or 13 weeks, or 13 weeks and 1 day. There are at least 4 weeks (28 days) in every month, but the number of â¦days varies. Some months have 30 days (April, June, September, November) and some have 31 days (January, March, May, July, August, October, December).
1540s ,  words , clauses , etc. inserted into a sentence ,  from Middle French parenthÃ¨se ( 15c. ) , from Late Latin parenthesis  addition of a letter to a syllable in a word ,  from Greek parenthesis , literally  a putting in beside ,  from parentithenai  put in beside ,  from para -  beside  ( see para - ( 1 ) ) + en -  in  + tithenai ...
Parentheses . Parentheses (always used in pairs) allow a writer to provide additional information. The parenthetical material might be a single word, a fragment, or multiple complete sentences. Whatever the material inside the parentheses, it must not be grammatically integral to the surrounding sentence. If it is, the sentence must be recast. This is an easy mistake to avoid. Simply read your sentence without the parenthetical content.