The company specializes in telecommunications.长途通信 Some kitchen tools have very little uti.用处 high utility bill公用事业 Telescopes and microscopes are optical instruments.光学的 He suffers from an optical defect 视觉的• The company specializes in telecommunications. • Some kitchen tools have very little utility. • high utility bill • Telescopes and microscopes are optical instruments. • He suffers from an optical defect. 长途通信 用处 公用事业 光学的 视觉的