Theory:

     Strangely, the wind had dropped. The trees were still, not a leaf moved. The crickets were silent in the grass. The crows flew round in a circle, then settled down for the night in an oak tree.

     ‘I must get home before dark,’ said Usha to herself, as she hurried along the path. But already the sky was darkening. The clouds, black and threatening, looked over Haunted Hill. This was March, the month for storms.

     A deep rumble echoed over the hills, and Usha felt the first heavy drop of rain hit her cheek.
 
     She had no umbrella with her; the weather had seemed so fine just a few hours ago. Now all she could do was tie an old scarf over her head, and pull her shawl tight across her shoulders. Holding the shopping bag close to her body, she quickened her pace. She was almost running. But the raindrops were coming down faster now. Big, heavy pellets of rain.

     A sudden flash of lightning lit up the hill. The ruins stood out in clear outline. Then all was dark again. Night had fallen.

     ‘I won’t get home before the storm breaks,’ thought Usha. ‘I’ll have to shelter in the ruins.’ She could only see a few feet ahead, but she knew the path well and she began to run.
Explanation :
 
Suddenly to her surprise, there was no wind, the trees were standing still, and the insect-crickets were silent. The crows flew in a circle and then settled under an oak tree.
 
Usha almost walked fast as she wanted to reach home before dark, but the sky was getting dark; the clouds were black over the haunted hill. It was March month, always had storms.
 
There was a rumble of thunder, and the Usha felt the first raindrop on her cheek.
 
Usha did not carry her umbrella because when she started, the weather was perfectly fine. So she took her scarf and tied it over her head and pulled her shawls across her shoulders. She held the shopping bag close to her body and walked faster, but the rain had already started, and it was heavy too.
 
Suddenly there was a bolt of lightning, and she could see the ruins. Again it was completely dark as it became night.
 
Usha was now sure that she could not reach home as the storm was heavy. She has to take shelter somewhere, maybe the ruins as it was just a few feet away. She ran to the ruins as she knew how to go there.
 
Meanings of difficult words:
 
Numbers
Word
Meanings
1.
Strangely
Surprising way.
2.
ThreateningTerrifying.
3.
Rumble Thunder, roar.
4.
Quickened
Become faster.
5.
Shawl A piece of fabric worn by women.
6.
PaceFootstep.
Reference:
State Council of Educational Research and Training (2019). Term-1 English Standard-7. The Wind on Haunted Hill by Ruskin Bond  (pp. 25-34). Published by the Tamil Nadu Textbook and Educational Services Corporation.