Our everyday lives (26) ____________such activities as sitting, walking, picking up things from the ground and lying in bed. None of these activities are possible in orbit. (27)____________a spacecraft reaches orbit, everything inside it seems to be weightless. Anything or anyone that is not tied down will float. Weightlessness allows astronauts to appear very (28)____________ . They can lift objects that would be (29)____________ heavy to move on Earth. But there are some drawbacks. (30)____________the effect of gravity, blood and other body fluids begin to flow towards the head. This can cause a feeling of headaches. With no gravity to push against, bones and muscles can become weak. To (31)____________fit, they have to exercise several hours each day. This allows them to recover more quickly when they (32)____________ to Earth. In a space shuttle or space station, there is no up or down. There is no difference (33) a floor and a ceiling. This can make astronauts feel (34) until they get used to this strange (35) . 26. A. relate B. involve C.consist D.own 27. A. Before B. During C.One time D.Once 28. A. strong B. strongly C.strength D.strengthen 29. A. a little B. much C.much more D.far too 30. A. With B. Without C.Lack D.Short 31. A. protect B. continue C.stay D.become 32. A. return B. turn C.come D.enter 33. A. among B. either C.between D.in between 34. A. diseased B. affected C.homesick D.sick 35. A. design B. arrangement C.direction D.location