【明報專訊】Teddy and his friends have discovered a worm in the garden and they don't know if it's coming or going. "It's a nice worm, but we can't make head or tail of it," someone said. Worms are like that, they seem to have a head at both ends. "Or maybe they have an end at both ends," Angela said. If you can't or are unable to make head or tail of someone / something, you don't understand or can't make sense of him / it. "Sometimes I'm unable to make head or tail of mathematics," Teddy said.