have/has been 后面跟动词ing形式，构成现在完成时时态，表示从过去到现在一直在做某事。
have/has been 后面跟过去式，构成过去完成时态。
I have been learning English for 3 years.
我已经学了三年英语。
Temperatures have been above average.
气温一直比平均温度高。
The marshes have been drained.
沼泽地里的水已排干。
Severe winds have been battering the coast.
狂风一直在海岸肆虐。
