Questions 18 to 20 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions.
Now, listen to the passage.
What is the speaker’s field of study

A．Insects that feed on plants.
B．Animals that feed on insects.
C．Plants that use insects to survive.
D．Insects that are attractive to plants.

A．The importance of function in the design of a building.
B．A number of modem American architects and the important elements in their work.
C．Three main elements that any architect must think when designing a building and a famous architect.
D．The important characteristics of the designs of one specific architect.