Theory:

Two roads diverged in a yellow wood,
And sorry I could not travel both
And be one traveller, long I stood
And looked down one as far as I could
To where it bent in the undergrowth;
Explanation:
 
The poet is talking about how he was walking down a road, and there were two different roads. He had to choose one of them. The poet says that as he was a single person, he could not travel on both roads. Yellow wood means a forest with leaves that are wearing out, and they have turned pale and yellow, and it is the season of autumn. It represents a world which is full of older people. The poet stood there for a long time and looked at the path very carefully. Before taking the path, he wanted to know how it was. He was able to see the road till from where it curved after which it was covered with trees and was not to be seen. It happens in our life also when we have choices, and we have to choose only one out of them, we take time to think about the pros and cons, whether it is suitable for us or not and only then, we decide on what path we should choose.
 
Meanings of difficult words:
 
Numbers
Word
Meanings
1.
DivergedSeparated and took a different direction.
2.
YellowwoodA forest with decomposing leaves.
3.
UndergrowthDense growth of plants and bushes (means the forest).
Reference:
National Council of Educational Research and Training (2006). Beehive. The Road Not Taken - Robert Frost (pp. 15). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.