I searched for "as if" - 8,170,000 and "as though"- 1,500,000. What does this show?
First of all, it shows that they are both correct as they have a high frequency. It also suggests that one is much more common that the other.
Does this have any implications for teaching the forms?
| Sun | Mon | Tue | Wed | Thu | Fri | Sat |
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | ||
| 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| 13 | 14 | 15 | 16 | 17 | 18 | 19 |
| 20 | 21 | 22 | 23 | 24 | 25 | 26 |
| 27 | 28 | 29 | 30 |

"As whether"- 228,000
I looked for “however” and it gave me 64,100,000, and some of these 64,100,000 examples were absolutely brilliant, hence I recon that the internet is a fast, cheap and very interesting means of learning language.
It's an excellent instant source of examples, but it does have some limitations- it's not very reliable for spoken English, as mopst is written, so it doen't cover all bases. ;-)
I bet quite a lot of those examples were useless, as well. It's a good tool for throwing stuff up, however.