"flowers in the garden" = "niwa de hana";"there are flowers in the garden" = "niwa ni WA hana ga arimasu";"I saw flowers in the garden" = "niwa de (watashi WA) hana o mimasu"
'Never say' would translate to: 決して言わないでください /kesshi* te i WA nai de ku da sai/ in polite Japanese. [*: the 'shi' syllable is pronounced geminated. When read together the 'i'...