A:17−12
B:2
C:4 2 ﹣4
D:433
第一个计算出圆周率的人是我国科学家( )。
用显微镜观察小鱼尾鳍内血液流动时,毛细血管的辨别特征是( )
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?