#1
The statement and its question tag must always agree in tense and auxiliary verb.
#2
'I am' always takes the tag 'aren't I?', never 'amn't I?' or 'ain't I?'
#3
Indefinite pronouns like everyone, everybody, someone, and nobody take the plural pronoun 'they' in question tags.
#4
Negative adverbs such as hardly, scarcely, seldom, rarely, and barely render a sentence negative, requiring a positive tag.
#5
Imperative sentences (requests/commands) take 'will you?' or 'won't you?' as standard question tags.
#6
'Let us' (Let's) takes 'shall we?', whereas 'Let him/them' takes 'will you?'.
#7
A semicolon connects two independent clauses without coordinating conjunctions; a comma splice error occurs when a comma alone joins them.
#8
Possessive pronouns (its, yours, hers, ours) never take an apostrophe.
#9
Capitalization is mandatory for proper nouns, days, months, and the first word of every direct quotation.
#10
The serial comma (Oxford comma) is placed before the coordinating conjunction in a list of three or more items for clarity.