Several changes:
-spelling
-reordering paragraphs for clarity
-rewrote some sentences
-added clarification for UDF being available across databases in an instance i.e. scope is not limited to a database when it is created.

Rewrote some sentences for readability.

Changed to: "In the above sample, `print_result` is used to simplify the printing of the result set. It is similar to `taos_use_result`"

Stylistic changes.
Clarifying changes.
Removed reference to taos_use_result since it is not mentioned in code snippet.

Minor changes for spelling and style.

Stylistic and grammar changes.

Grammar changes.

Spelling correction.

Spelling correction
Stylistic changes

Some stylistic changes.
Some clarifying changes.

There was an odd sentence in this doc, I updated it to reflect what is written in the Chinese version.

Grammar updates to Data Subscription page.

Grammar updates to the Continuous Query page

Grammar updates to Developer Guide > Select Data

Small grammar updates.

Some grammar updates to Inserting Data > SQL

Small grammar edits.

Made grammar changes to the Data Model page.

Made some grammar and reworded the differences between connectors.

Great work Jeff, this is a very helpful page. I changed the content for the second point to make it easier to follow.