Business English 10th Edition by Mary Ellen Guffey,Carolyn Seefer

تمرين 73

Insert necessary commas. In the space provided, indicate briefly the reason for the comma or its absence (for example, independent adjectives, introductory verbal phrase, introductory clause , and so forth). Write C if the sentence is correct.
PictureTel a subsidiary of IBM released the first PC-based videoconferencing system in 1991. ________________