Fill in the gaps with suitable preposition, articles and zero articles:

Washing hands regularly is (a) ----  important activity. It keeps us safe (b)---- corona-virus. How you wash your hand is also very (c)----- important. First, you have to wet your hands (d) ------ clean, running water and apply soap. Then, rub your hands together with (e)------soap to create foam. Lather the backs of your hands, (f) -----your fingers and (g) ----- Remember, you have to scrub your hands (h) ------ at least 20 your nails. seconds. After that rinse your hands well with clean and running water. Finally, dry your hands using (i) ---- clean towel or tissue paper. Learn the process (j) ----- washing hands and also educate your friends about it.

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.