Change the verbs between brackets into the correct forms: active or passive. How Mirrors are Made? a. The first step in manufacturing any mirror is cutting the outline of the glass "blank" to suit the application. If the mirror (be) for an automobile, for example, the glass will be cut out to fit in the mirror mount on the car. Very hard, finely pointed blades (use) to do the cutting. Diamond scribes or saws, sharp metal points with diamond dust embedded in them, are often used because the diamond will wear down the glass. Cutting (be) usually (do) (apply) before the metal coating because the coating may flake off the glass as a result of the cut. An alternative for cutting the glass to form blanks (be) mold the glass in its molten state. to b. Blanks are then placed in optical grinding machines. The blank-filled base (place) against another metal plate with the desired surface shape flat, convex, or concave. A grinding compound, a gritty liquid, (spread) over the glass blanks as they (rub) or rolled against the curved surface. Finer and finer grits are used until the surface is very smooth and even. c. When the glass surfaces are shaped appropriately and polished to a smooth finish, they (coat) with whatever reflective material the designer has chosen. Regardless of the coating material, it (apply) in an apparatus called an evaporator. The method of coating (create) very uniform and highly reflective surfaces d. Several evaporation steps are then combined to make a multiple-layer coating. Clear dielectric materials may (evaporate) on top of metal or other dielectrics to change the reflective or mechanical properties of a surface. Mirrors with silvering on the back of the glass, for instance, often (have) an opaque dielectric layer applied to improve the reflectivity and keep the metal from scratching. One-way mirrors (be) the exception to this procedure, in which case great care must be taken not to damage the thin metal coating. e. Finally, when the proper coatings have been applied, the finished mirror (mount) in a base or packed carefully in a shock resistant package for shipping. ​