题目

---Tom, keep your_____ on your studies.    --- Sure, mum. I'll keep that in_____. A. mind;mind      B.heart;head     C. brain; mind      D.heart;brain   答案：Akeep one's mind on sth专心做某事;keep sth in mind记住某事。若函数f（x）=1beax的图象在x=0处的切线l与圆C：x2+y2=1相离，则P（a，b）与圆C的位置关系是（　　）A、在圆内B、在圆上C、在圆外D、不确定，与a，b的取值有关