Re: Is it fine to use "because" at the begining of a sentence in writing?
I'll give a longer answer.
Q: Why did the chicken cross the road?
A: Becaues he wanted to get to the other side.
-- Back in elementary/primary school, the teacher would mark this answer down. The teacher wanted complete sentences. "The chicken crossed the raod to get to the other side." It's only half a sentence as written.
In real life, we'd answer that way all the time, or simply "He wanted get to the other side."
So a "sentence" like "Because he wanted to" would be correct in most real-life contexts, but incorrect in many school settings.
However, you can also write a complete sentence starting with "because" by changing the order. "Because the chicken wanted to get to the other side of the road, he walked across it."
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.