Tending to be put back among present participles (3)
I believe the answer is:
apt
'tending' is the definition.
(I know that tending can be written as apt)
'put back among present participles' is the wordplay.
'put back' says the letters should be written backwards.
'among' indicates a hidden word.
'tpa' is hidden in the letters of 'present participles'.
'tpa' written backwards gives 'APT'.
'to be' acts as a link.
(Other definitions for apt that I've seen before include "Suitable for Pat" , "Suitable, appropriate" , "Liable" , "Fitting - inclined" , "Befitting" .)