Is starting an answer to a question with so proper English?

It's not grammatically incorrect to start an answer with "so," but it's often considered informal and can sound awkward in formal writing.

Here's a breakdown:

* "So" as a conjunction: This is the most common use of "so." It connects two clauses and indicates consequence or result. For example: "The rain was heavy, so we stayed inside."

* "So" as an intensifier: This is less formal and can sound childish. For example: "So you're saying you don't want to go?"

Alternatives to starting with "so" in formal writing:

* "Therefore"

* "Consequently"

* "As a result"

* "Thus"

Example:

Informal: "So, the answer to your question is..."

Formal: "Therefore, the answer to your question is..."

In casual conversation, starting with "so" is perfectly acceptable and often used for emphasis or to transition smoothly between ideas. However, it's best to avoid it in formal writing to maintain a professional tone.