In this task, you are given a sentence from the research paper and your task is to classify the given sentence into the following categories: Background (Why is this problem important? What relevant works have been created before? What is still missing in the previous works? What are the high-level research questions? How might this help other research or researchers?), Purpose (What specific things do the researchers want to do? What specific knowledge do the researchers want to gain? What specific hypothesis do the researchers want to test?), Method (How did the researchers do the work or find what they sought? What are the procedures and steps of the research?), or Finding (What did the researchers find out? Did the proposed methods work? Did the thing behave as the researchers expected?). 

Example Input: surgical masks and homemade masks when worn during a variety of activities by healthy volunteers and a simulated patient.
Example Output: method

Example Input: This study intended to investigate the utilization of Chinese medicine ( CM ) for respiratory symptoms by patients with a medical history of TB in Taiwan.
Example Output: purpose

Example Input: this is the first report of experimental data for both the site of O-glycosylation and identity of the O-glycans attached on the subunit S1.
Example Output:
finding