Then I used a microscope to count and measure the phytoplankton present.
(I; used; a microscope; to count and measure the phytoplankton present; T:Then) Context(I used,List([5, 11))):(I; used a microscope to count; ) Context(I used,List([5, 11))):(I; used a microscope to measure; the phytoplankton present)
I used,List([5, 11)) I used,List([5, 11))
I I I
used used a microscope to count used a microscope to measure
a microscope to count and measure the phytoplankton present T:Then
the phytoplankton present