have been trading
Have been trading is the present perfect continuous tense. Using have, been and the -ing form of a verb like this means that what is being talked about has begun in the past and is still happening. They traded in the past and they trade now.
more information: present perfect continuous tense
dampers
A damper is a sort of bread.
paid
Here paid is the past tense of the irregular verb pay. Follow the link below to find out more and to listen to some examples.
more information: pay
grown
Grow is the past participle of the irregular verb grow. Follow the link below to find out more and to listen to some examples.
more information: grow
even out
distribute equally; make level
Example: I wish we could even out the rainfall so we get a bit each day instead of a big flood followed by a drought.
sold
Here sold is the past participle of the irregular verb sell. Follow the link below to find out more and to listen to some examples.
more information: sell
spoken
Spoken is the past participle of the irregular verb speak. Follow the link below to find out more and to listen to some examples.
more information: speak