original: Many specialize in machine construction, medical equipment, international trade, optics and electronics.
simplifications: Specialties are machine construction, medical equipment, international trade, optics and electronics. Many of them make imachines, medical equipment, international trade, optics and electronics. Many specialize in machine construction, medical equipment and several other industries. Many are experts in machine construction, medical equipment, international trade, optics, and electronics. Many specialize in machine making, medical equipment, international trade, optics and electronics. Many focus on machine construction, medical equipment, international trade, optics and electronics. Many focus on building machines, medical equipment, international trade, optics, and electronics. Many are skilled in machine construction, medical equipment, international trade, optics and electronics. A lot of them specialize in machine construction, medical equipment, international trade, optics and electronics. Many are experts in building machines, medical items, overseas trade, optics and electronics.