a) It’s possible that the stones for Stonehenge were moved by a system of levers.
might
The stones for Stonehenge __________ by a system of levers.
b) It is almost certain that the material to build the Sphinx of Giza was transported down the Nile. must
The material to build the Sphinx of Giza _____ down the Nile.
c) The construction of the Great Pyramid of Giza probably involved up to 50,000 workers.
could
The construction of the Great Pyramid of Giza _ _____up to 50,000 workers.
d) Perhaps the Nazca Lines in Peru were a map of underground water supplies. May
The Nazca Lines in Peru ____ a map of underground water supplies.
e) The Easter Island statues obviously didn’t come from outer space.
can’t
The Easter Island statues _____from outer space.
f) Machu Picchu was almost definitely built as a fortress against powerful enemies. been
Machu Picchu _ as a fortress against powerful enemies