n summary, to sum up, to conclude\r2 . ?;?;\r1)?; Years ago a TV set was regarded as a luxury. Today it is a necessity.\r2)?;: Discrimination is mainly practiced against women in the field of science.\rWe don't find men complaining about this.\r3 . ;?;\r1); An electron tube is generally used for amplification. Vacuum tube is\ranother name for this device.\r2)?; Yesterday a pigeon carried the first message from London to Liverpool.\rThe bird covered the distance in two hours..\r4 .;\rBrain injuries do not heal as do hurts in other parts of the body. A broken leg can be set. A\rblack eye clears up. But the brain, once damaged, never recovers. The destruction of brain\rcell is permanent.