Interchange of Sentences

The book is so heavy that I cannot carry it.

Step 1: 'Too + adjective + to + verb' structure expresses impossibility or difficulty. Step 2: 'So...that' structure needs to express the same meaning of impossibility. Step 3: Replace 'too' with 'so' and add 'that' followed by a negative clause. Step 4: 'Cannot/could not' maintains the meaning of impossibility from 'too...to'. Step 5: Option B changes meaning to possibility, C is incomplete, and D has incorrect grammar.

No sooner did the rain stop than children went out to play.

Step 1: 'As soon as' in simple past tense converts to 'No sooner...than' with inversion. Step 2: Since original sentence uses simple past 'stopped', we use 'did' + base form 'stop'. Step 3: The structure is: No sooner + did + subject + base verb + than + second clause. Step 4: Option B lacks auxiliary verb, Option C uses past perfect unnecessarily, Option D uses wrong verb form 'stopped' instead of 'stop'. Step 5: Inversion is mandatory with 'No sooner'.

Mumbai is one of the most crowded cities.

Step 1: Comparative degree compares two entities - Mumbai and Delhi. Step 2: To convert to superlative, we need to compare among many entities, not just declare it the most crowded. Step 3: 'One of the most crowded cities' is appropriate as it suggests Mumbai ranks among the top crowded cities. Step 4: 'The most crowded city' would be too absolute without mentioning the group being compared. Step 5: Options C and D have grammatical errors and don't use superlative degree properly.

Although it rained heavily, the match continued.

Step 1: 'Despite' is followed by a noun phrase, while 'Although' is followed by a complete clause. Step 2: Convert the noun phrase 'heavy rain' into a clause with subject and verb. Step 3: 'It rained heavily' is the most natural way to express the action. Step 4: Option B lacks a verb, making it grammatically incorrect. Step 5: Options C and D are grammatically correct but less natural than the standard 'it rained heavily' construction.