Translation of "Hmm" in Japanese

Hmm, did we have some breadcrumbs?

えーと、パン粉は有ったかな？

Hmm. I have a feeling I'm going to get lost whichever road I take.

ウーン、どっちの道に行っても迷いそうな気がする。

"Well, there's something I'd like your advice on about my research project ..." "Let's see... Hmm, you're investigating flowering plants then."

「じつは自由研究で相談したいことがあって・・・」「どれ・・・。ふーん、被子植物について調べてるのね」