现在完成时的结构是助动词have /has + 过去分词。英语be动词 ( am，is，are)的过去分词是been，所以句子中有be动词时，其现在完成时应该是助动词have / has + been + 其他。
例句
Prices have risen alarmingly.
价格涨得吓人。
Building costs have nosedived.
建筑费用猛跌下来。
Prices have fallen dramatically.
价格突然暴跌。
They have failed lamentably.
他们的失败让人惋惜。
