The expression can be used every time that one thinks another doesn't take their necessary efforts to achieve something as if saying: you can't make it because you haven't eaten your meal so you don't have that energy.
It can be used as a hurry-up to urge someone to put more energy/effort on something.
It can be a blame, ironic, etc depending on how you use ...
It means the coach thinks the players are not energetic enough as if they were hungry.
This sentence can only be used in some situations:
a coach blames the players being not energetic enough
an officer blames the soldiers being not powerful enough
fighter ridicule the opponent being so weak
or similar. Always considered as a blaming or ridiculing.
If you ...
You could use 要 or 該 to represent "Time to A".
Time to sleep:
Time to leave here or go to somewhere:
In certain contexts, 去 also means "Time to A". E.g 去睡覺 去洗澡
But 該走了 can't use 去 to replace 該. 去走了 is incorrect.
I don't think there's a fixed expression to reliably translate "time to X".
According to the context, there's a few ways to go about it, that I can think of right now.
When X is broad in scope, and the "time" period you are talking about doesn't mean necessarily right now, you can use 时刻. It often translates to "the ...
Axel Tong answered A而B之 perfectly. I would address some other idiom structures not mentioned in the question
Becky 李蓓 wrote:
Note that x而y之 is just one example, and there are others like 千x万y
[(adjective A) + (noun A) + (adjective B) + (noun B)] / Example: 千丝万缕，如狼似虎
[(adverb A) + (adjective A) + (adverb B) + (adjective B)] / Example: 穷凶极恶，巨奸大恶
[adverb A] ...
It seems that there are two types of 成语 represented by the same “structure”.
A而B之 could mean “action + action, done to something (third person pronoun)”.
取而代之 means “to take and replace 之 (something that was previously mentioned)”. Compare this to 取代, which simply means “replace”. You could consider 取而代之 a literary form of 取代; using it adds elegance to an ...