Fill in the blanks with suitable prepositions, articles and zero articles.

 Bangladesh is a free land but she is beset (a) ----- many problems. The use of poly bags is very dreadful. Recently it has become (b) ------ great threat (c) ----- our environment (d) ----- used poly bags block the drainage system As a result, the low-lying areas (e) ---- the towns and the cities go under (f) ------ dirty water when it rains heavily.The used poly bags also destroy (g) ----- fertility of our soil. Our government has already banned the production (h)poly bags. Yet some greedy and (i) ---- dishonest businessmen are the bags (j) ---- their own interest.

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.