用“what, why, which, when, how"填空，完成下面的疑问句。（注意首字母要大写）

1. ____________ is Li Ming doing?  He is reading a book.

2. ____________ did you go to Shanghai?  By plane.

3. ____________ do you like winter?  Because I can ski.

4. ____________ season do you like best?  Fall.

5. ____________ did you come to Canada?  At 7: 00.