import os

class TextFinder:
    def __init__(self, folder):
        self.folder = folder

    def find_matches(self, text):
        matches = []
        files = os.listdir(self.folder)

        for file in files:
            file_path = os.path.join(self.folder, file)
            if os.path.isfile(file_path):
                with open(file_path, 'r', encoding='utf-8') as f:
                    content = f.read()
                    index = content.find(text)
                    while index != -1:
                        start = max(content.rfind('\n', 0, index), content.rfind('.', 0, index))
                        end = min(content.find('\n', index), content.find('.', index))
                        if start != -1 and end != -1:
                            matches.append(content[start+1:end].strip())
                        index = content.find(text, index + 1)

        return matches

# Example usage:
if __name__ == "__main__":
    finder = TextFinder('example_folder')
    matches = finder.find_matches('text_to_find')
    print(matches)