YOU SAID:
Hello, I've been working so hard
INTO JAPANESE
こんにちは、私はとても頑張ってきました
BACK INTO ENGLISH
Hello, I've been working very hard
INTO JAPANESE
こんにちは、私はとても頑張ってきました
BACK INTO ENGLISH
Hello, I've been working very hard
That didn't even make that much sense in English.