When I arrived at the warehouse , they have already loaded half of truck.
When I arrived at the warehouse , they have already loaded the truck halfway.
When I arrived at the warehouse , they have already loaded the truck half.
When I arrived at the warehouse , they have already loaded half of truck in a half way.
When I arrived at the warehouse , they have already loaded the truck up to the half of its capacity.
Do all these sentences mean the same? Are all uses of “half” correct?