[单项选择]
Directions: In this part of the test, you
will hear several short talks and conversations. After each of these, you will
hear a few questions. Listen carefully because you will hear the talk or
conversation and questions ONLY ONCE. When you hear a question
read the four answer choices and choose the best answer to that question. Then
write the letter of the answer you have chosen in the corresponding space in
your ANSWER BOOKLET.
A. (A) Disintegrating comets.
B. (B) Gases in the atmosphere.
C. (C) Underground water that rose to the surface.
D. (D) Water vapor.