Answers:
- Pronoun: Someone; Circled Word: is
- Pronoun: None; Circled Word: belong
- Pronoun: Some; Circled Word: melts
- Pronoun: Everybody; Circled Word: has
- Pronoun: Many; Circled Word: were
- Pronoun: Neither; Circled Word: was
- Pronoun: Most; Circled Word: understand
- Pronoun: No one; Circled Word: was
- Pronoun: Everyone; Circled Word: wants
- Pronoun: Someone; Circled Word: has
- Pronoun: Everything; Circled Word: is
- Pronoun: Half; Circled Word: arrive
- Pronoun: Each; Circled Word: seem
- Pronoun: All; Circled Word: are
- Pronoun: Nobody; Circled Word: wishes
- Pronoun: All; Circled Word: is
- Pronoun: All; Circled Word: are
- Pronoun: Many; Circled Word: attends
- Pronoun: Anybody; Circled Word: has
- Pronoun: One; Circled Word: bite
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Step-by-step explanation:
The singular indefinite pronouns are:
- Another
- Anybody
- Anyone
- Anything
- Each
- Either
- Everybody
- Everyone
- Everything
- Much
- Neither
- Nobody
- No one
- Nothing
- One
- Somebody
- Someone
- Something
The plural forms are:
- Both
- Few
- Many
- Others
- Several
Then there are indefinite pronouns that could either be singular or plural depending on context.
- All
- Any
- Most
- None
- Some
For instance, we could say "Some dog is barking" (singular) and "Some of the dogs are barking" (plural). Take note of the very slight difference in wording. Also, take note of the "is" and "are".
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With all that in mind, you should have enough info to a) determine the indefinite pronoun and b) determine if you have a singular or plural form.
In problem 1, "Someone" is the indefinite pronoun. It's in the "singular" list so we go for "someone is". The full sentence being "Someone is knocking at the door".
For problem 2, "none" is in the gray area. It could be singular or it could be plural. Notice that "none of the marbles" can be replaced with simply "none". The sentence "None of the marbles belong to Lucy" is the same as "None belong to Lucy". Though of course the first sentence is more descriptive, while the second relies on implicit context cues from somewhere else.
The other sentences will use the same idea.