Hi all, I'm fairly new to Mandarin and I have just purchased this tool and I am on the third lesson and it's talking about negating verbs and it only uses pinyin (no characters) and the thing it uses for 不 is not bù like I've seen on other sites, but bú (rising tone instead of falling). Now, I know that when you have two third-tones together the first one transforms into a rising tone because it's easier to pronounce that way. Is there some rule that would change the falling stress to become rising stress (it occurs just before yào) or is this software just plain wrong? (It's telling me that I don't want = Wǒ bú yào.) Xiè xie.