【单选题】听力原文: Many scientists had very bad proficiency records in their school days. Famous inventor Thomas Edison, for instance, did so poorly in his first years of school that his teacher warned his parents...
A.
They were top students.
B.
They went to best public schools.
C.
They were not very good students.
D.
Their teachers thought they would be very successful.
【简答题】An investor is evaluating a set of bonds from which he will select two issues. The investor’s objective is to find bonds with cash flows that will precisely match a known stream of future obligations....