【单选题】听力原文:W: The bookstore has run out of the textbook assigned by Dr. Martin. M: He didn't expect so many students to take his class this semester. Q: What do we learn about this situation? (18)
A.
Dr. Martin didn't want so many students in his class.
B.
The students were supposed to buy the textbook earlier.
C.
The bookstore is going out of business.
D.
Dr. Martin didn't order enough textbooks for his students.