A：{x|0＜x≤3}
B：{x|1≤x≤3}
C：{x|0≤x≤3}
D：{x|1＜x≤3}
— Nowadays more and more foreigners are becoming interested in Beijing Opera.
—That's true. It's an important part of Chinese____________.
用方框中所给的短语的适当形式填空。
hear from, arrive at, be good at, as well, be afraid of
已知正三棱台的上下底面边长分别为1和4，侧棱长为2，则此棱台的高为（ ）
