Mmm, I'm not so sure that's a good idea.

　　嗯，我不知道這想法行不行。

　　LL: Are you sure this is a good idea?

　�。▏�(yán)肅地）當(dāng)然是個(gè)好主意嘍！怎么會(huì)不是好主意呢？

　　I'm not sure that's a good idea.

　　我不能確信那是一個(gè)好主意。

　　Are you sure it's a good idea taking this back to yours?

　　你確定放在你那是個(gè)好主意嗎？

　　If you're entertaining foreigners, be sure you have a good idea of their business practices!

　　如果你打算招待外國(guó)客戶，一定要掌握他們的商業(yè)習(xí)慣。