Inventor John Friedman created a prototype of the ﬁrst ﬂexible straw by inserting a screw into a paper straw and, using
dental ﬂoss, binding the straw tightly around the ______ When the ﬂoss and screw were removed, the resulting corrugations
in the paper allowed the straw to bend easily over the edge of a glass.
screw’s thread’s.
screws’ threads.
screw’s threads.
screws threads’.
Choice C is the best answer. The convention being tested is the use of plural and possessive nouns. The singular possessive
noun “screw’s” and the plural noun “threads” correctly indicate that there is only one screw and it has multiple threads.
Choice A is incorrect because the context requires the plural noun “threads,” not the singular possessive noun “thread’s.”
Choice B is incorrect because the context requires the singular possessive noun “screw’s,” not the plural possessive noun
“screws’.” Choice D is incorrect because the context requires the singular possessive noun “screw’s” and the plural noun
“threads,” not the plural noun “screws” or the plural possessive noun “threads.’”