All we know that mobile phone is the most (a)___ invention of modern science. Now a days, it is very (b)___ for us. At (c)___ it is very small and light. (d)___ changes have been brought about in (e)___ communication by mobile phone. The whole (f)___has now become smaller and (g)___ in respect of communicating information. But it is (h)___ that mobile phone has some (i) ___ too. Over all, it is a great (j) ___ for mankind.

We are not ungrateful to the freedom fighters.

Their contribution is the greatest thing. 

An imperative sentence expresses a command, request, advice, or suggestion. It typically starts with a base form of a verb, and the subject 'you' is often understood but not stated. To form a negative imperative, 'Do not' or 'Never' is placed at the beginning of the sentence.

In the given sentence, "You should never disrespect or forget our martyrs," 'should never' indicates a strong suggestion or advice against an action. To transform this into an imperative sentence, we remove the implied subject 'you' and the auxiliary 'should', directly starting with 'Never' to convey the strong negative command or advice.

Our government has built the national memorial with a view to paying tribute to their memories. 

 (e) A freedom fighter is greater than any other son of the soil.

Our independence was got/gotten by us for their sacrifice.