Basic conversion

I'm converting an old BASIC program to VB and I'm a little confused on some of the BASIC syntax. I have this:

VB Code:

50 DefDbl C, E, S, X-Z
60 Dim C(4, 4), x(30), XX(30), y(30), YC(4, 30), EF(4, 30), EP(4, 30)
70 Dim OK$(4), OS$(4, 30), yy(30), yyy(30)

at the beginning of the program.
1) these variable names suck arse.
2) what does OK$(4) mean? Is that a string array of 4 elements?
3) Why do they define several doubles and then dimension one of them as an array? (e.g. C)

I'm just trying to understand it.

Hope this helps.