Fill in the blanks with suitable words.

Scientists have recently reported that (a) ----- surface ice caps are (b) ----- This is due to a rise  (c) ----- atmospheric temperature known (d) ------ the greenhouse effect. According to the scientists,the carbon dioxide is primarily responsible (e) temperature rise in (f) ------. The carbon dioxide is high when coal and oil (g) ------ burnt.The gas is accumulating (h) ----- the atmosphere and causing the temperature to rise. As a result, the polar ice in the North and South poles (i) ------ melting. We should maintain the ecological (j) ------ of the environment.

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.