I'm not following. 我有点不明白了。

　　I don't get it. 我不懂。

　　I'm confused. 我有点晕。

　　I don't really understand. 我不太明白。

　　That's not clear.? 我不清楚。

　　I can't see your point. 我不明白你在说什么。

　　I'm not sure what you mean.我不明白你的意思。

　　I don't have any idea what's going on. 我压根不知道是怎么回事。

　　It's over my head.? 太难懂了。

　　It's beyond me. 我完全不能理解。