给定一篇文章，将其中的标点符号和数字去掉，只保留单词，并计算每个单词的出现次数。
“Pandas are a bear species native to the East Asian region. They are easily recognized by their distinctive black and white fur markings.”
单词           | 出现次数
-------------|--------
Pandas       | 1
are          | 1
a            | 1
bear         | 1
species      | 1
native       | 1
to           | 1
the          | 2
East         | 1
Asian        | 1
region       | 1
They         | 1
easily       | 1
recognized  | 1
by           | 1
their        | 1
distinctive | 1
black        | 1
and          | 1
white        | 1
fur          | 1
markings     | 1