They continue to explore length using nonstandard units, and standard units of measurement are introduced (centimeter, inch).
(standard units of measurement; are introduced; ) (They; continue; to explore length using nonstandard units) Context(They continue,List([0, 13))):(They; continue to explore; length) Context(They continue to explore,List([0, 24))):(They; continue to explore length using; nonstandard units)
They continue,List([0, 13)) They continue to explore,List([0, 24))
standard units of measurement They They They
are introduced continue continue to explore continue to explore length using
to explore length using nonstandard units
length
nonstandard units