have has been doing是什么时态

回答

爱扬教育

2022-03-18

have has been doing是过去完成进行时时态。
have：vt. 有; 持有; 占有; 由…组成; 显示出，带有(性质、特征)。
has：有; have 的第三人称单数现在时形式。
been：v. 曾经; 曾经到过(某地)。
doing：n. 所做的事; 发生的事; 所作所为。

扩展资料

　　Biological systems have been doing this for billions of years

　　生物系统亿万年来一直都是这样。

　　Some scientists have been doing research on artificial internal organs.

　　一些科学家一直在研究人造内脏。

　　And that is just what Aclima, a new firm in San Francisco, has been doing over the past few months.

　　这也正是旧金山一家名为Aclima的新公司过去几个月以来一直在做的事情。

　　The government has been doing some blue-sky thinking on how to improve school standards.

　　就如何提高学校的水平，政府仍然在作一些漫无边际的构想。

　　He has been doing this sort of work for years.

　　他干这一行有年头了。