17.
A. Some students at the back cannot hear the professor.
B. The professor has changed his reading assignment.
C. Some of the students are not on the professor's list.
D. The professor has brought extra copies of his assignment.
18.
A. She doesn't want to talk about the contest.
B. She's modest about her success in the contest.
C. She's spent two years studying English in Canada.
D. She's very proud of her success in the speech contest.
