成人英语三级考试

【单选题】I think Father would like to know ______ I've been up to so far, so I decide to send him a quick note.
A. which
B. why
C. what
D. how

网考网参考答案：C
网考网解析：
[考点] 此题考查be up to sth．“忙于某事”的用法 [解析] to在这里作介词，需用疑问代词A、C两项作宾语，但用which须有选择范围。 查看试题解析出处>>