Theory:

     Then suddenly Taro stopped chopping. What was that sound he heard? Could it be, could it possibly be rushing water?
 
     Taro could not remember ever seeing or hearing a rushing stream in that part of the forest. He was thirsty. The axe dropped out of his hands and he ran in the direction of the sound.
Explanation:
  
All of a sudden, Taro heard a sound. He stopped chopping and turned his attention towards the sound. It had felt like the sound of a rushing water to him.
 
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Rushing Water
 
He was surprised to hear the sound because he had never seen or heard a water source in that part of the forest. He was so thirsty that he dropped his axe. He then started running towards the water.
 
axe.png
Axe - a tool used by the woodcutter
 
Meanings of the difficult words:
  
Sl. No.
 Words
Meanings
1
PossiblyHopefully; may be.
2
RushingMoving with speed; flowing fast.
3
Stream
A small or narrow river.
4
Axe A tool used for chopping wood.
Reference:
National Council of Educational Research and Training (2006). Honeysuckle. Taro’s Reward (pp. 29-34). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.