Let's eat apples is accepted, but Let us eat apples is not? I wouldn't often use the latter either, but duo is often "complaining", offering the extended version of apostrophed shortcuts as "another translation" (let's - let us, don't - do not, it's - it is etc)
The meaning is not the same:
- "let us eat apples" is a command to a third party and would translate to "laisse-nous manger des pommes" or "laissez-nous manger des pommes".
I have to correct you on the English. "Let's eat apples" means exactly the same thing as "let us eat apples". "Let's" is just a contraction of "let us", nothing more. Both sentences can be translated as 1) "mangeons des pommes", 2) "laisse-nous manger des pommes" and 3) "laissez-nous manger des pommes". It just depends on whom you're addressing. If you're asking Abella to eat apples with you, use "mangeons". If you're asking Tristan to allow you and Abella to eat apples, use "laisse(z)-nous manger".
Not quite. I agree with you that "let us eat apples" can mean the same thing as "let's eat apples" -- a suggestion that we eat apples -- but a plea to someone else to be allowed to eat apples can't be either phrase, but only "let us eat apples."
"Let us" for "let's" seems to be considered as archaic by most dictionaries today.
Since it is the imperative mood, first-person plural, it is "let's eat apples". The expression "eat some apples" is 2nd person, which may be either "mange des pommes" or "mangez des pommes".
"eat apples" is a command given to one or more people = mange des pommes ! (tu) or mangez des pommes ! (vous)
"mangeons des pommes" is a command given to one or more people + the speaker = let us eat apples.
It is the imperative mood. Unlike Spanish, for example, French does not drop the subject pronoun for anything other than the imperative. I.e., the French "mangeons" (here) will always be taken as "let's eat", never as "we eat" or "we are eating".