Quizzes: Subject Verb Agreement 1

For the following questions, determine whether the verb should be singular (ending in -s) or plural (not ending in -s) in order to agree with its subject.

1) Jupiter, whose existence was recognized by astronomers of ancient times, (has/have) long been associated with the mythologies of many cultures.
2) While drivers throughout the United States are required to purchase automobile insurance, coverage levels often (varies/vary) depending on the driver's age and state of residence.
3) In contrast to many other Roman amphitheaters, which (was/were)located in outlying neighborhoods, the Colosseum was constructed in the city center, placing it both literally and symbolically at the heart of Rome.
4) Cycle racing, like all popular sports, (flourishes/flourish) to a great extent because of the mythology that has grown up around it.
5) The Great Fire and the Panic of 1873 (was/were) responsible for the collapse of the Riverside Improvement Company, an event that brought new construction in the Chicago area nearly to a halt in the late nineteenth century.
6) Although there (is/are) millions of different types of viruses in existence, only about 5,000 of them have been conclusively identified by scientists.
7) The Black Sea coast is characterized by the presence of steep mountains that (extends/extend) along the entire length of the coast, separating it from the inland Anatolian plateau.
8) In the eighteenth century, the first public library in the United States and the first fire department in the state of Pennsylvania (was/were) founded by Benjamin Franklin.
9) Tropical waves in the Atlantic basin frequently (develops/develop) from disturbances that begin in east Africa and drift over the continent into the Atlantic Ocean.
10) California, which leads the United States in the production of vegetables, (produces/produce) much of its fresh fruit as well.
11) Formed by ice particles mixed with smaller amounts of rocky debris and dust, the rings of Saturn (contains/contain) several gaps whose origins have not yet been fully explained.
12) Elemental iodine, which dissolves easily when it is exposed to most organic solvents, (is/are) only slightly soluble when placed in water.
13) While many beneficial health effects have been found from eating apples, there (is/are) several forms of allergies that have been linked to various proteins found in that fruit.
14) The California sycamore, which can reach a height of over 100 feet, (provides/provide) food for the many birds and small mammals that feed on their twigs and bark.
15) The wings of a butterfly are sophisticated collectors of solar energy because their elongated rectangular scales (overlaps/overlap) to create a structure resembling shingles on a roof.
16) Vampire bats, which often consume no food for nearly a week, (uses/use) their noses to detect heat when blood in their prey is close to the surface.
17) Intricately worked patterns and an enthusiastic use of color (has/have)made kente cloth recognizable throughout the world.
18) In addition to sketching landscape and nature in his early years, M.C. Escher also drew insects, which (was/were) featured in a number of his later works.
19) Gravitation, best known as the force that (gives/give) weight to objects with mass, also causes objects to fall to the ground when dropped.
20) Researchers have hypothesized that whales sing by pumping air into pouches, which then (releases/release) vibrations into the surrounding water.