he start learning english since three years____.A.before B.ago
问题描述：
he start learning english since three years____.A.before B.ago
答
B.ago,since后面加过去的时间.
不明白的再问哟,请及时采纳,多谢!还是不懂 before不是暗示这完成时么He has learned English for three years before.但在since后面加的就是具体的过去时间。