21. Air blowing over a fairly warm sea _____ with moisture.
a. the quick saturation
b. quickly becomes saturated
c. it becomes saturated quickly
d. to saturate it quickly



22. A church built in the Gothic style _____ pointed arches.
a. often has
b. often having
c. to have often
d. it often has



23. The rings _____ are made of billions of chunks of ice.
a. they circle Saturn
b. are circling Saturn
c. circle Saturn
d. circling Saturn



24. The largest volcano _____ in the solar system is Olympus Mons, on Mars.
a. found
b. it is found
c. is found
d. finds



25. _____ is the scientific definition of work.
a. A force moves an object
b. For the moving force of an object
c. A force moving an object
d. A force is moving an object



26. _____ as money were certain kinds of cowries.
a. The shells were most widely used
b. Because of the wide use of shells
c. The shells most widely used
d. They used shells widely



27. A primitive, undersea animal resembling a garden cucumber _____.
a. a sea cucumber is called
b. is called a sea cucumber
c. to call a sea cucumber
d. calling a sea cucumber



28. Sails made of cloth tied onto timber supports _____ power early windmills.
a. were used to
b. the use of
c. using
d. they used



29. A single _____ through a magnetic field flies in a spiral path.
a. moves an electron
b. electron is moving
c. electron moving
d. electron moves



30. Immunity _____ from disease or from vaccination is called active immunity.
a. is acquired
b. acquired
c. it is acquired
d. acquires



31. The bony sword _____ the upper jaw of a swordfish makes up about one-third of its length.
a. extending from
b. it extends from
c. extends from
d. is extending from



32. _____ to the U.S. Supreme Court was Sandra Day O’Conner, in 1981.
a. The woman had been appointed first
b. For the appointment of the first woman
c. The first woman appointed
d. The first woman was appointed



33. Energy coming from the hot, molten rock inside the earth _____.
a. geothermal energy
b. the energy is geothermal
c. to be geothermal energy
d. is geothermal energy



34. The Mariana Trench, located within the Pacific Ocean, _____ on Earth.
a. on the lowest point
b. is the lowest point
c. to lower the point
d. the point is lowest



35. _____ from the sleep disorder narcolepsy is seized with sudden and irresistible attacks of sleep.
a. For a person to suffer
b. A person suffers
c. A person is suffering
d. A person suffering



36. The white grains _____ tapioca pudding come from the roots of the cassava.
a. are used in
b. their use in
c. used in
d. they are used in



37. A typical mountain _____ in the tropical regions has four to five different weather zones.
a. is rising up
b. it rises up
c. rises up
d. rising up



38. The 880 to 1,000 _____ in Africa today can be grouped into four families with common origins.
a. languages are spoken
b. speak the languages
c. they speak the languages
d. languages spoken



39. Rain, wind, and streams working through old limestone _____ in Utah’s Bryce Canyon.
a. produced the rock spires
b. producing the rock spires
c. the production of rock spires
d. rock spires were produced



40. A boy’s suit supplemented with an extra pair of pants and a cap _____ from the Montgomery Ward catalog for $2.25 in 1895.
a. the purchase was available
b. available for purchase
c. was available for purchase
d. the available purchase