some algorithms to identify of a pattern in text data I have few sentences like below in my project(around 25000),  

sentence1 = 'Must be able to multi-task in a fast-paced, deadline-driven environment'
sentence2 = 'Strong organisational skills and proactive approach'
sentence3 = 'in this role you will design develop and revise application simulations in alignment with product implementation timelines'
sentence4= 'ensures appropriate cross-referencing between documents within and across qms chapters/topics'


From these sentences, I am trying to determine what functionality is being expected from the person or like what person has to do. I need to identify those keywords. I can use any ML techniques or any other method to determine the keywords,

for example in 

sentence1 = [multi-task, fast paced, deadline-driven environment]
senetence3 = [design develop and revise application simulations]


I tried to identify those words with help of POS but that wasn't very useful. Are there any algorithms or ideas or methods that can detect such keywords ?
Since you don't seem to have any annotated data, the best you can do is probably this:


Optional first step: remove stop words (there are many such lists available, for example https://pythonspot.com/nltk-stop-words/)
Calculate the Inverse Document Frequency for every word in the vocabulary. This is intended to measure the importance of a word based on how often it's used, in the sense that a word used in fewer sentences makes it more important for these sentences.
Calculate TF-IDF for every word in a sentence, then rank the words by their TF-IDF weights. In general the top ones are supposed to be the most relevant. Optionally you can decide to select the top N words as keywords.