问题补充：
It Jack twenty minutes the math problem yesterday.
A. took; to work out
B. takes; worked out
C. has taken; work out
D. is taking; working out
答案：
(答案→)A. took; to work out
B. takes; worked out
C. has taken; work out
D. is taking; working out
解析：可联系答.案.网客服索取。
