15. The volcano has erupted approximately once every ten years_________ 1970. A. since B. in C. from D. for 16. The Braille___________ enables blind and visually impaired people to read and write. A. email B. note C. code D. report 17. ___________ occurs when two people look at each others eyes at the same time. A. Eye contact B. Conversation C. Chatting D. Talking 18. In the future, people will communicate brain-to-brain, using___________. A. telepathy B. blog C. holography D. messenger 19. In a message board you can________ messages or post questions. A. raise B. arrive C. text D. leave 20. Arms crossed over the chest is an example of ___________ A. text messages B. chat room C. videoconferencing D. body language 21.She posted a question on __________ board and got many interesting answers. A. cyber B. media C. internet D. message 22.They have never met ________before. They only chat on Facebook. A. eye to eye B. face to face C. head to head D. hand to hand 23. I hope you __________ when I arrive at 8 p.m. today! A.didn't work B.won't be working C.don't work D. wont work 24. Science and technology are the keys__________ economic and social development. A. for B. to C. in D. of 25. The ___________ in technology allow astronomers to know more about outer space. A. developments B. science C. exploration D. discovery 26. Alexander Graham Bell was a great ___________, who invented the telephone. A. developer B. conservationist C. scientist D. explorer 27.Students can meet a career _______ and discuss what they should do. A. inventor B. adviser C. programmer D. developer 28. Astronauts use ___________ to move around when they are on the Moons surface. A. spaceships B. flying saucers C. space cars D. moon buggies 29. ___________ is important because it may help to solve the problems of overpopulation and exhaustion of resources on Earth. A.Space exploration B.Space travelling C.Space checking D.Space walking 30.To generate cheap and clean energy, instead of burning fossil fuels, scientists have developed ___________. A.oil B.solar panels C.electricity D.coal burning