-english has large vocabulary,hasn't?
-yes,(know)more words and expressions and you will find it easier to read and communicate
这是祈使句

（knowing）anything about it，i will tell you all
这是现在分词短语作条件状语

作单选怎么区别啊？

-English has large vocabulary,hasn't?
-Yes,(know)more words and expressions and you will find it easier to read and communicate
这是祈使句
（Knowing）anything about it，i will tell you all
这是现在分词短语作条件状语
作单选怎么区别啊？

know more words and expressions and you will find it easier to read and communicate.
这是并列句，中间有and。“… and you will”一看就是个祈使句，所以用动词原形。

（Knowing）anything about it，I will tell you all.
中间是逗号，后面一句已经有谓语，所以填空的一定是非谓语，在doing、done、to do中选择。不是表目的（“为了能了解任意情况，我会告诉你一切”明显不符合逻辑），排除to do。因为know和I是主动关系，所以用现在分词。填进去后分析两者的逻辑关系，也就是条件。
现在分词作状语，也可改成对应的从句。（此处是条件状语从句）
Knowing anything about it，I will tell you all.
=If I know anything about it, I will tell you all.

ps：原句是你写的还是书上的？我觉得应该有个a，“a large vocabulary”。