There was a math problem last night, and I racked my brains and couldn't figure it out. Just as I was, (I don't know the true face of Lushan Mountain, only in this mountain), my father came over, and with a little help from him, I was suddenly enlightened. It's really (there is no road to doubt, and there is another village. )

There was a math problem last night, and I racked my brains and couldn't figure it out. Just as I was (a mouse was gnawing at the sky and had nowhere to eat), my father came over, and with a little help from him, I was suddenly enlightened. It's really (there is no way to solve doubts, and a village is clear. )