def combine_datasets(train_set, val_set):
    """
    Combine two datasets in one.
    """
    # Extract individual arrays.
    train_inputs, train_labels, train_masks, train_sentences = train_set
    val_inputs, val_labels, val_masks, val_sentences = val_set
    
    # Combine respective arrays.
    combined_inputs = train_inputs + val_inputs
    combined_labels = train_labels + val_labels
    combined_masks = train_masks + val_masks
    combined_sentences = train_sentences + val_sentences
    combined_set = (combined_inputs, combined_labels, combined_masks, combined_sentences)
    return combined_set