单项选择题


Questions 18 to 20 are based on the following passage. At the end of the passage, you will he given 15 seconds to answer the questions.
Now, listen to the passage.
If an object weighed one pound on the surface of the earth, how much would it weigh 4,000 miles above the earth

A.3/4 pounds.
B.4 pounds.
C.1/9 pound.
D.1/4 pounds.