题目

The fifth generation of mobile technology, or 5G, promises to bring lightning—fast data connection speeds. Not everyone is excited about 5G service, however. 【1】 There are even protests (抗议）to stop companies from setting up the equipment necessary for 5G service. Why are they so worried?To understand the possible health risks of 5G, it's important to understand how 5G is different from 3G and 4G.【2】 It will be used to transmit (传输) data and 5G uses a different part of the electromagnetic spectrum (电磁波谱). The signals have short wavelengths measured in millimeters calThe old professor gave orders that the experiment 　　　　 before 6. A. was finished　 B. will finish　 C. be finished　　 D. shall be finished