—We usually go hiking for vacation. I like it, but I want to try something more challenging this year.

—_____

A．Cheer up!

B．Like what?

C．Take care.

D．Let’s go.

关于阿尔茨海默病的早期核心症状主要是（）。

A.性格改变

B.记忆减退

C.言语功能障碍

D.幻觉

E.谵妄