sentence: Researchers should not give up when they face difficult problems with the research and should keep trying different ways to solve them and they will do it in the end .
modified: Researchers should not give up when face hard problem with the research and keep try by different ways to solve it and they will do it at the end .
transformation: PRON, ADJ, NOUN:NUM, VERB:TENSE, VERB:FORM, PREP, PRON, PREP