选择与画线部分意思相同或相近的选项。
1. Today is Tuesday. I have lots of homework to do. I'm really busy.
A. not free
B. tired
C. strict
D. relaxed
2. Tom has lunch al 12:00 with his classmates at school.
A. eat
B. have
C. takes
D. eats
3. My father works from Monday to Friday.
A. on weekdays
B. on Friday
C. on Saturday
D. in the day
4. We don't have any classes on weekends.
A. on Wednesday
B. on Monday
C. on Saturday and Sunday
D. on weekdays
5. Mother's Day is in the fifth month of the year.
A. March
B. April
C. September
D. May
，且a≠b，记｜a-b｜=m，求a-b与x轴正方向的夹角的余弦值。
