In Bev Kong's science class, lab groups have just finished separating a mixture of iron filings, salt, water, and sand into its various parts and accounting scientifically for how they did it.
(lab groups; separating; a mixture of iron filings, salt, water, and sand; into its various parts and accounting scientifically for how they did it) (they; did; it)
lab groups they
separating did
a mixture of iron filings, salt, water, and sand into its various parts and accounting scientifically for how they did it
it