—How long have you been going to work on foot?
—Since last month when I from a heart attack.
A. recovered
B. have recovered
C. was recovering
D. would recover
网友回答
(答案→)A. recovered
B. have recovered
C. was recovering
D. would recover
解析：A 考察动词时态。句义：你步行上班已经多长时间了？—自上个月我心脏病康复开始。Last month是时间点，应该与过去时连用。故A正确。