May i say "children were given an essay on the theme "my last holidays in nature" for homework" or it is grammatically incorrect? I have a big problem with articles. please help me! Thanks in advance.
Also, note that you should alternate double and single quotes. Otherwise you're quoting, "children were given an essay on the theme " and " for homework".
Otherwise it sounds OK to me.
'In (the) nature' is the equivalent in many languages of the English 'in the country/mountains', 'in the great outdoors', 'at the seaside' or some similar expression.