A:2,π3
B:2,-π3
C:2,2π3
D:2,2kπ+π3,k∈Z
看图,读一读,选择适当句子补全对话。
A. Would you like some milk?
B. We can read books at home.
C. Good idea.
D. How is the weather in winter?
E. Why don't you play football?