一种新药杰克:我发明了一种新药能有效地杀死虱子。汤姆:太棒了。怎么用呢?杰克:你捉到一只虱子,只要在它嘴上抹一点这种药,虱子就会死去。

• Tom: That's wonderful. How is it used? Jack: When you catch a louse, just put a little of that drug on its mouth and it will die immediately.