Need help reading this drawing

I am having trouble reading this drawing.

First, how would I draw a 4-10x20 Oblong hole? (First picture)

Second, why are there two dimensions for L1, L2, L3, and L4? (Second picture)

First. A couple of circles and a couple of lines; trim as required would be one option.

Second. Perhaps because the part was going to be made in two different sizes?

First, how would I draw a 4-10x20 Oblong hole?

There are 4 oblong slots 10mmx20mm - I would use the circle, line and trim commands.

Second, why are there two dimensions for L1, L2, L3, and L4?

Looks like a single drawing depicting two different configurations for the part (table).

There are 4 oblong slots 10mmx20mm - I would use the circle, line and trim commands.

 

 

 

Is the 20mm from the center of the circle or quadrant?

I believe that would be a center-to-center distance although I've seen it both ways.

Is the 20mm from the center of the circle or quadrant?

When dimensioned like that it is usually overall dimensions.

If you look at it, then if those end radii were full circles they would meet at the centre line. So 10 wide by 20 overall length.

(I would draw the two paralell lines and use the fillet command to do the ends).