Direct/indirect: He said, ‘I shall go as soon as it is possible.’

D. He said that he would go as soon as it is possible

Conversion to Indirect Speech:

• The reporting verb “said” is in the past tense.
• “Shall go” in direct speech expresses a future intention.
• When the reporting verb is in the past tense and the direct speech talks about the future, we use “would” + base verb to maintain the future meaning in the indirect speech.
• “It is possible” remains the same because it’s a state that doesn’t depend on the tense of the reporting verb.

there’s an exception to this rule when dealing with clauses that express:

• Universal truths
• Habitual actions
• States of being

In the sentence “He said, ‘I shall go as soon as it is possible’”, the clause “as soon as it is possible” expresses a universal truth. The possibility itself doesn’t change based on when the reporting happens. So, even though the main verb (“shall go”) is backshifted, the verb in this dependent clause remains in the present tense.