你好,正确答案是：
1.have studied
2. Li ming is already ten years old.
3.He came back late yesterday.
4.I will write to my mother tomorrow evening.
5.He will go there by plane some day next year.

祝你学习进步,更上一层楼! (*^__^*)
不明白的再问哟,请及时采纳,多谢!原因第一题：since是现在完成时的标志第二题：already放在be动词后第三题：yesterday是过去时第四题：tomorrow evening是固定搭配，表将来时第五题：some day next year表示明年的某一天，也表示将来 请及时采纳 ~