The easiest of narrations is of facts and universal truths. No change is made in the tense and syntax of reported speech because you cannot convert them into past, and it will be illogical to convert anything that contains universal fact into past tense, like you can never say; earth was round, Light was made of seven colours or stars were far away from the earth. Facts are always treated as present. The reported speech will be used in indirect narrations quite as it is.
Perhaps the only change in the sentences containing facts and universal truths is the use of conjunction (that) in indirect narration when comma and quotation marks are removed. That is also known as demonstrative as you have learnt in previous chapters but here it acts as conjunction because it connects dependent clause (reporting speech) with independent clause (reported speech).
The verb of reporting speech in indirect narrations is converted into (tell) or (inform) in accordance with the situation of the sentence. Since there is a great difference between say, tell and inform. Say refers to any statement whereas tell and inform denote some type of information and facts.
Remember, the verb say is the only verb that is followed by preposition (to) whereas all others like; ask, tell, inform etc are not followed by any preposition.
He said, “Two and two make four.”
He told that two and two make four.
Teacher said to the class, “earth revolves around
Teacher told the class that earth revolves around the sun.
She said, “Water boils at 100 degree.”
She told that water boils at 100 degree.
He said, “There are seven days in a week.”
He told that there are seven days in a week.
He says, “The colour of day-sky is blue.”
He tells that the colour of day-sky is blue.
He said, “Diamond is the hardest element.”
He told that diamond is the hardest element.
Our grammar teacher said, “Sentences are separated
by full stop.”
Our grammar teacher told that sentences are separated by full stop.
She said, “Dark clouds are sign of rain.”
She said that dark clouds are sign of rain.
The nature of some facts is rather temporal and after some time they cease to be facts. In this case once they are replaced by the latest information they are no longer treated as fact and such sentences can be converted into past tense in indirect speech provided the direct speech is in past tense. Now look at the example.
He said, “There are 115 elements.”
This sentence may be treated as fact before 2010 but not now of course. And it should be converted into past in indirect narration like;
He told that there were 115 elements.
This example is clearer if we add;
He told that there were 115 elements and now there are 118.