下文是《新外研社八年级下册Module 4 Unit 2》中activity  2的课文：                                           

                                                           Healthy living

       I was not feeling very well so the doctor checked my heart and said I needed more exercise. I have never been very active, and I do not like sports.I have always wanted a pet,so my parents gave me a dog for my birthday.Now I get exercise by takeing him for a walk every day.I have had him for three months now and I feel really healthy.        

--Anna

     Our teacher decided to start a girls' football team and I thought, “What a great idea!”  I was the first member of the team.We have played football for a year now and we all feel very fit.Our teacher is the coach,and she also takes part in training with us.She is in excellent condition too.

 --Wang Wei

      For the last few years,I went to work on the underground.When I got to work,I always felt very sleepy and I was not happy.I bought in January.Since then, it has become part of my life.Now I ride to work every day. It is my daily exercise. I arrive at work with a smile on my face.

--Thomas

     I was weak after a long illness, so I wanted to exercise more.Then a friend suggested, “Why don't we go for a run befor school?” So we started running a week ago. But I do not enjoy running,and when I get to school, I feel awful. My leges hurt and I am hot all over. Perhaps I am too weak to do any exercise.What do you think?

--Richard

彩色部分不太懂（下面按照顺序）：

1. 请问“I was not feeling very well”为什么要用过去进行时？

2. 请问这个蓝色的“for”在那里是什么意思？

3. 有in excellent condition那么有没有out of excellent condition？

4. 请问这句话为什么不用现在完成时？

   练习题里就有一题：In the last twenty years,our city has improved a lot.这里是用现在完成时，可是课本上的那句为什么不用现在完成时而用一般过去时？我还是有点儿搞不清，能说一下吗？

5. 这句话“ Since then,it has become part of my life.”我最不明白了，become不是短暂性动词吗？为什么这个时候还可以与since then连用？为什么不是用“Since then,it has been part of my life.”？

麻烦各位专家老师了，谢谢！！