单选题 We finally received the fax ______ Monday, which was three days later than we expected.
A. on
B. in
C. as
D. at

【正确答案】 A

【答案解析】与表示星期几的词语一起使用的介词是(A)选项on。(B)选项in与月份连用，(D)选项at与时间点连用。