Should money be written as 1000 in 20s or with an apostrophe between the 20 and the s?
20s is correct.
Is it grandma's and grandpa's house or grandma and grandpa's house?
Given that grandma and grandpa are probably conceived as a unit, or partnership, rather than separately, I would favor the latter construction, grandma and grandpa's house. However, the other form would also be acceptable.
Is there an apostrophe in year's wage?
Yes, the wage belongs to the year (as such) and therefore a possesive apostrophe is needed.
Should there be apostrophe in Mens when used as signage for the Mens Toilet?
Yes because the toilet is the mens. So it would be men's toilet.
Would our last name be written as The Oswalt's or The Oswalts'?
Neither, it would be written The Oswalts - with no apostrophe. Plurals don't need apostrophes. If something belongs to you, use an apostrophe. The Oswalt's house.
Does the word houseplants need an apostrohpe?
No, not if you want the simple plural form of the word.
How to use an apostrophe for fire fighters?
"My son liked to play with a fire-fighter's helmet" and "It was the fire-fighters' opinion that the fire could be put out" (several of them) and "it was the fire-fighter's opinion that the fire could be put out" (just one with an opinion).
Should there be an apostrophe after the word members when you say the members of the community?
No there shouldn't be an apostrophe.
Where does the apostrophe go for the word prefects?
prefects' It is plural. If not, and if it is singular, prefect's.
All the prefects' books were vandalized.
The prefect's book is vandalized.
Do you need apostrophe in its?
You only use an apostrophe in it's when it is a contraction of it is.
If you are using ITS to describe something belonging to IT, such as "It was wagging its tail," then the tail belongs to it and so its does not have an apostrophe.
Do you insert an apostrophe in the word 'tomorrow' in the sentence 'tomorrows answers today'?
Yes there should be an apostrophe. Tomorrow's answers today.
If you're referring to one client: client's contention
If you're referring to more than one client: clients' contention
When should you use a apostrophe?
Use an apostrophes as in a professional name like St. Mark's House not if you are only saying Marks house.
No, your doesn't have an apostrophe. You're, however, does have an apostrophe because it's a contraction for you and are.
How do you correctly place possessive apostrophes when there is more than one noun?
The class of Mr. Wood at Washington High School would be best expressed as 'Mr. Wood's class at Washington High...' or 'At Washington High, Mr. Wood's class...'
Shortening the term to 'Washington's Wood's class' assumes that the listener knows that 'Wood' is a person and that 'Washington' is a school, which may not be the case. That form would only be appropriate in casual conversation with people who were familiar with these facts.
Does monkeys require an apostrophe?
Not if you're talking about more than one monkey. You use an apostrophe to make a noun possessive. The monkey's behavior is odd, for example.
Do you need an apostrophe before the s in others if say drew others attention to?
No. But you do need one after the s, because others is plural.