What is the test for determining the intent of the legislative body in the construction of statutory language?

"In construing the statutory language the primal principle of statutory construction requires the ascertainment of the intent of the legislative body (Moyer v. Workmen's Comp. Appeals Bd. (1973) 10 Cal.3d 222, 230 [110 Cal.Rptr. 144, 514 P.2d 1224]; Select Base Materials v. Board of Equal. (1959) 51 Cal.2d 640, 645 [335 P.2d 672] ...), this court having no power to rewrite an ordinance or statute so as to make it conform to a presumed intention which is not expressed. [Citation.]" (County of Madera v. Superior Court, supra, at p. 668, 114 Cal.Rptr. 283.)