Last summer I took a course on _____ poisonous gases. [ ]

A. how to deal with

B. what to deal with

C. how to be dealt with

D. what to be dealt with

古诗“去年今日此门中，人面桃花相映红。人面不知何处去，桃花依旧笑春风。”所表现的是一种______联想。

A．对比
B．接近
C．自由
D．相似