The low-lying land was very marshy
the construction of a complex system
of drainage ditches was necessary
before construction could begin.
the
the
the
A. marshy the construction of a
complex system of drainage
ditches was
B. marshy, the construction of a
complex system of drainage
ditches was
C. marshy, so the construction of a
complex system of drainage
ditches being
D. marshy, so the construction of a
complex system of drainage
ditches was
tis
the