They will observe the changes taking place over a period of two weeks and record their observations on the data sheet.
(They; will observe; the changes taking place over a period of two weeks) (the changes; taking; place; T:over a period of two weeks) (They; record; their observations on the data sheet)
They the changes They
will observe taking record
the changes taking place over a period of two weeks
place T:over a period of two weeks
their observations on the data sheet