过去完成时态形式为had helped,可举例为Before I could say anything,he had helped me finish the task.在英语中,过去完成时的结构为had+动词的过去分词,用来表示某一行为或动作发生在另一事件发生之前,即表示的时间为“过去的过去”,如By the time I arrived at the bus stop,the bus had left.