运行图能够反映数据随（）变化而发生的变化。
参考答案：时间
---Mr Wang, I have trouble ________ the text.
---I’m sure you can, but remember ________ it at least three times.
A．to understand; reading
B．understanding; reading
C．to understand; to read
D．understanding; to read
简述外交的特点
