Yesterday Andy _____ his dictionary to me, and said I could _____ it for a week.
A:lent; borrow
B:borrowed; have
C:lent; keep
D:gave; keep
____ ____ does Grace do online shopping?
双曲线 x2a2−y2b2=1 (a>0,b>0) 的渐近线为正方形OABC的边OA,OC所在的直线,点B为该双曲线的焦点。若正方形OABC的边长为2,则a=____.