havebeendoing是什么時(shí)態(tài)用法

have been doing是現(xiàn)在完成進(jìn)行時(shí)。
例句：
The car must have been doing at least 100 miles an hour.
這車(chē)速肯定每小時(shí)至少100英里。
I have been doing some historical research.
我一直在進(jìn)行史學(xué)研究。