Today I would like to share an amazing website with you: ctext.org On this page you can find ALL the Chinese classics (most with English translations). The cool thing about the page is that the navigation of the Classics is very easy and divided into different Time Periods (Dynasties) and the whole content can be searched for specific keywords. So, for instance, if you are interested about the evolution of a certain character you can easily find out about its frequency in different time documents. Let's take the character 是 as an example. 是 in ancient texts did not stand for 'to be'. It had several other meanings, one of the most important meanings being a demonstrative pronoun. When searching for 是, you can easily check different time documents where 是 is appearing and find out easily when it has been used for the first time as a copula verb meaning ’to be'.