问题补充：
The professor has given us advice on how to improve our memory.
A. much
B. many
C. a lot
D. several
答案：
(答案→)A. much
B. many
C. a lot
D. several
解析：
试题分析: 句意：教授已经给了我们许多关于如何提高记忆的建议。much许多（修饰不可数名词），many（修饰可数名词）许多， a lot许多（名词），several几个（修饰可数名词）。give advice提建议，advice不可数名词，故选A
