ending_names = ["ending0", "ending1", "ending2", "ending3"]
def preprocess_function(examples):
     first_sentences = [[context] * 4 for context in examples["sent1"]]
     question_headers = examples["sent2"]
     second_sentences = [
         [f"{header} {examples[end][i]}" for end in ending_names] for i, header in enumerate(question_headers)
     ]