【正文】
ack twenty times. be B. will have been go D. will have gone 3. Many ways have been found_____small and simple machine to process large and plicated machine parts. A. by using B. to use C. using D. used 4. I walked down the corridor, my footsteps_______frighteningly through the empty deserted building. A. echoing B. echoed C. to echo D. having echoed 5. Apart from personal preferences, social context also affectsboth directly and indirectlythe media and the media content to which you bee exposed. For example, other members of the family often select media content that you _____, and you bee exposed to it. A. would not have selected B