A telescope, like a microscope, enables us to see things which we could not see without it
. A microscope magnifies things(or features of things)which are so small that they are invisible to the naked eye. They may be as small as a cell or even a small group of molecules. "Micro" in Greek, and in several English technical words, means "small". But "tele" in Greek means distant or far away. The word "television" is also derived from this Greek word. In England, Australia, and New Zealand we call a television set the "telly", which is almost the same as the Greek word. In the United States people call it a TV. A telescope enables us to see objects which, though millions of times larger than ourselves, appear much smaller because they are so far away. Even the images of stars which we see through a telescope are, of course, greatly reduced in size in comparison with the stars, actual size. But a telescope enables us to see stars which are invisible to the human eye as well as giving us a brighter, clearer image of those which are visible. In the last twenty or thirty years there has been a great improvement in the design and magnifying power of telescopes. There are now some very large and powerful telescopes in existence. When you see the sun rise in the morning you are eight minutes late. What is the meaning of this strange statement? The fact is that it takes eight minutes for the light to travel from the sun to the earth. The speed of light is approximately 186,000 rails per second. When you see a planet with or without the help of a telescope you are again too late to see the planet as it exists when you look at it. You see it as it was some time earlier. What happens when you observe stars beyond the solar system? Light from these stars takes a much longer time on its journey. In many cases it takes millions of years to reach our planet. Perhaps you believe that when you see a particular star, you and the star exist simultaneously. But this cannot be true. Be tween you and the star there are many millions of miles in space; and this means that there is also a long history of several million years between the star and you; in other words, the star which you are looking at now no longer exists in the form. in which you see it. Perhaps at this moment there is no star at that particular point in space. Stars, like human beings, are born and die.
A microscope______.
A.may be as small as a cell or a small group of molecules
B.is similar to a telescope
C.enables us to see things that are invisible
D.enables us to see things that are too small to be seen