nouns ending with (not to be confused with substantivated adjectives) are written with instead of in prepositional: – "streaming – in lower streaming of a river". (as none of these endings are ever stressed, due to vowel reduction the pronunciation difference between and may be hardly noticeable in fluent speech.) but if words and are representing compound preposition meaning "while, during the time of", they are written with -е: "in a time of an hour". for nouns ending in , , or , using in the prepositional (where endings of some of them are stressed) is usually erroneous, but in poetic speech it may be acceptable (as we replace with for metric or rhyming purposes): "" (f. tyutchev).