There are two kind of "h" and one of them are silent all the times. The "h" in haricots is of that kind.
No, I think that "some green beans" should be accepted. Try reporting it next time
I think you can say "some" only where there is a "du" or a "de la" and not "des".
"Des" (here) is the plural of "un". There is no counterpart in English for this word. Some people feel it necessary to use "some" in an effort to translate each and every word. In reality, this sense of "some" is almost always ignored in English.
How do you tell when it is 'ate,' 'eating,' 'is/am eating,' and so on? Mange, mangent, mangez.
In French 'I eat' and 'I am eating' is said in one way: 'je mange'. 'Ate' is past tense, so it would be, 'je mangeais' (imparfait) or 'j'ai mangé' (passé composé).
Additionally, "mange" is the present tense conjugation of manger for "je" and "il/elle/on" (first and third person singular). "Mangent" is for "ils/elles" and "mangez" is for "vous"
What have green beans got to do with clothing - which is the title of this section.