400 Must Have Words for the TOEFL » LESSON 8 - Energy

Word List
  • combustion [kəmˈbəstʃ(ə)n] n.
    The process of burning
    When air quality is poor, combustion of materials in a fireplace is prohibited.
    Usage tips     Combustion is often followed by of.
    Parts of speech     combust v., combustible adj.
  • component [kəmˈpoʊnənt] n.
    One part of a system or whole
    Their home theater system has a number of separate components.
    Usage tips     Component is often followed or preceded by of.
  • convey [kənˈveɪ] v.
    To transport from one place to another; to transmit or make known
    A messenger conveyed the prince’s letter to the commander of the army.
    Parts of speech     conveyance n., conveyor n.
  • discretely [dɪˈskriːtli] adv.
    Separately; distinctly
    In order to understand how the engine worked,each component needed to be studied discretely.
    Parts of speech     discrete adj.
  • nucleus [ˈn(j)ukliəs] n.
    A central or essential part around which other parts are gathered; a core
    The nucleus of many European cities is the town square.
    Usage tips     Nucleus is often followed by of.
    Parts of speech     nuclear adj.
  • permeate [ˈpərmiˌeɪt] v.
    To spread or flow throughout; to pass through or penetrate
    The smell of cooking permeated the entire apartment building.
    Parts of speech     permeation n.
  • rotate [ˈroʊˌteɪt] v.
    To turn around; to take turns in sequence
    The planet rotates on its axis once every 14 Earth days.
    Parts of speech     rotation n.
  • solar [ˈsoʊlər] adj.
    Of,or relating to, the sun
    The ancient society kept time with a solar calendar.
  • source [sɔrs] n.
    The point of origin or creation
    The reporter was unable to identify the source of the information for his story.
    Parts of speech     source v.
  • trigger [ˈtrɪɡər] v.
    To set off or initiate
    I was certain any mention of politics would trigger a big argument.
    Parts of speech     trigger n.

TOEFL Prep I Complete each sentence by filling in the blank with the best word from the list.Change the form of the word if necessary. Use each word only once.

  • combustion
  • convey
  • permeate
  • source
  • trigger
  1. It is often difficult to __________ the meaning of a poem to a large audience.
  2. The __________ of the gossip was someone inside this office.
  3. Her bad mood that day __________ the atmosphere in the laboratory.
  4. The internal __________ engine revolutionized the way automobiles run.
  5. A cigarette __________ the explosion.

TOEFL Prep II Find the word or phrase that is closest in meaning to each word in the left-hand column. Write the letter in the blank.

______ 1. rotate(a) separately, as an individual part
______ 2. solar(b) spin on an axis
______ 3. component(c) sun
______ 4. discretely(d) center
______ 5. nucleus(e) part

Answer Key
TOEFL Prep I
  1. convey
  2. source
  3. permeated
  4. combustion
  5. triggered
TOEFL Prep II
  1. b
  2. c
  3. e
  4. a
  5. d
Answer Key

TOEFL Success Read the passage to review the vocabulary you have learned. Answer the questions that follow.

Most of the electricity in the United States is produced in steam turbines. There are many discrete steps in this process. In a steam turbine, Energy 39 combustion of coal, petroleum, or natural gas heats water to make steam. The steam rotates a shaft that is connected to a generator that produces electricity. Finally, that electricity is converted by a transformer and conveyed from the turbine to its place of use. Many sources can provide energy to heat the water in a steam turbine. Coal is primary, producing 51 percent of the country’s electricity. Another common way to heat water for steam turbines is through nuclear power. In nuclear fission, atoms of uranium fuel are hit by neutrons, triggering a continuous chain of fission that releases heat. In 2001, nuclear power generated 21 percent of the electricity in the United States. Solar power produces less than 1 percent of the United States’ electricity needs, because it is not regularly available and harnessing it is more expensive than using fossil fuels. Dependence on electricity permeates daily life in the United States. Still, few people are aware of the many components of electricity production.

Bonus StructureIn this context, still means “even so; despite this.”

  1. What does the author say about solar power?
    • a. It produces more electricity than any other source.
    • b. It is a relatively small source of energy for heating water in steam turbines.
    • c. Electricity producers are trying to use it more regularly.
    • d. Researchers are trying to make it cheaper to use.
  2. In the passage, the word transformer probably refers to a
    • a. truck
    • b. generator that produces electricity
    • c. type of turbine
    • d. device that changes electric currents
Answer Key
Answer Key
  1. b
  2. d
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