The term "mental food" (last sentence) refers to ______
A.books
B.grassland
C.brains
D.subjects
In the first sentence of the last paragraph, the pronoun"this"refers to______.
A.survey
B.question
C.answering
D.personal interviewing
The word "operation" (para. 4) refers to______.
A.sports activities
B.hunting
C.farmers
D.prey killing
The underlined word "one" refers to ______.
A.a woman
B.a man
C.a name
D.an act