Should "hand" go in the plural in this idiom "like the back of their hand(s)"?
Grammarly corrects me to use the plural, but I doubt it.
I think it's the doubt of the same origin as "they had to make up their mind(s)."
Idioms – “Like the Back of Their Hand” or “Like the Back of Their Hands”
idioms
Related Solutions
Only who is correct there.
If you wanted to use what or which, you'd have to reference the person/group you are talking about.
For example, these sentences are all correct.
Which actress do you like for the best actress at tomorrow’s Oscar’s?
What actress do you like for the best actress at tomorrow’s Oscar’s?
Which team do you like for the soccer game tomorrow night, Brazil or Germany?
What team do you like for the soccer game tomorrow night, Brazil or Germany?
The idiom, who do you like for..., is primarily just used when asking someone which person, school, team, etc they want to win at something. It's a very common phrase when asking someone who they think will win in any type of competition.
Here are some more examples of how this is used :
Who do you like for homecoming king and queen?
Who do you like for president?
Who do you like for the Kentucky Derby horse race?
Good question. Fascinating NGram supporting Kate's comment about back in the day being a recent development.
Google Ngram Back in The Day vs Back in the Days
To some extent your sentences are not interchangeable. Your second sentence should read something like -
Back in the days of paying rent, we had an apartment with a swimming pool.
Which is like saying -
Back in the day, when we were renters, we had an apartment with a swimming pool.
Back in the Day, is a slangy way of saying, when I was younger or some time ago. The phrase is usually followed by a anecdote describing what someone experienced or how they behaved in their past.
Back in the day, we had to change TV Channels by turning a tiny knob on the TV.
Back in the days is the more traditional usage of the phrase and its usage is slightly different. It is used to establish a time frame and is intended to be more specific than its slangy counterpart. It is generally followed by some illustrative phrase, often starting with the word 'of', intended to establish a time period.
Back in the days of black and white television, we changed channels by turning a tiny knob.
Best Answer
Singular "hand", for the gender-neutral "their". This is the case when need a third-person pronoun, but don't want to use "his" or "her".
(That is too casual for a job specification, it is just to illustrate the point)
But perhaps plural "hands" for plural "their".