Many words or phrases can be used to set up an explanation. The most common is because (or “because of”), but others have their uses. Here are alternatives and a discussion of their uses and their merits.
1. As: As is a direct synonym for because (for example, “He opted not to go see the movie, as it had gotten poor reviews”), but it’s inferior.
2. As a result of: This phrase is a substitute for “because of,” not because, as in, “As a result of his intervention, the case was reopened and they were ultimately exonerated.”
3. As long as: This informal equivalent of because is used to express the thought that given that one thing is occurring or will occur or is true, another is possible, in such statements as, “As long as you’re going, could you pick some things up for me?”
4. Being as (or being as how or being that): This phrase has the same sense-and the same formality-as “as long as.”
5. Considering that: This phrase is essentially identical in meaning to “as long as” and “being as” and its variants.