第1个回答 2014-10-17
用现在完成时。
In/During the past three years / Over the three years, he has frequently written letters to me,encouraging me to make more friends and telling me the way to learn / of learning English well.本回答被提问者和网友采纳
第3个回答 2014-10-17
"Three years, he wrote to me many times, encouraged me to make more friends, tell me the way to learn English well.