Theory:

     Nothing offered for some little time, and then he remembered hearing the doctor tell about a certain thing that laid up a patient for two or three weeks and threatened to make him lose a finger. So the boy eagerly drew his sore toe from under the sheet and held it up for inspection. But now he did not know the necessary symptoms. However, it seemed well worthwhile to chance it, so he fell groaning with considerable spirit. But Sid slept on unconscious. Tom groaned louder, and fancied that he began to feel pain in the toe. No result from Sid.

     Tom was panting with his exertions by this time. He took a rest and then swelled himself up and fetched a succession of admirable groans. Sid snored on. Tom was aggravated. He said, “Sid, Sid!” and shook him. This course worked well, and Tom began to groan again. Sid yawned, stretched, then brought himself up on his elbow with a snort, and began to stare at Tom. Tom went on groaning.
Explanation:
 
Suddenly, he remembered a doctor say that there is an illness that the patient has to be on the bed for two to three weeks or even lose a finger. Now he got something in his mind, he pulled his bed sheet and looked at his sore toe. He did not know the symptoms, neither he had any. He tried this trick and was making sound like he had lots of pain. Sid did not bother to look at him.
 
Tom was now overacting to get all the attention he can. He calmed down for some time and made more sound now and called out on Sid. Sid had to get up, he yawned and with his elbows got up. Tom continued his action.
 
Meanings of difficult words:
 
Numbers
Word
Meanings
1.
Groaning
Deep sound conveying pain, despair.
2.
Exertions
Physical or mental effort.
Reference:
State Council of Educational Research and Training (2018). Term-1 English Standard-7. On Monday morning - Adapted from The Adventures of Tom Sawyer by Mark Twain (pp. 18-21). Published by the Tamil Nadu Textbook and Educational Services Corporation.