Choose the appropriate word from the options given to complete the following sentence.
The newest fibre optic cables that carry telephone calls are made of glass so______ that a piece 100 meters thick is clearer than a standard windowpane.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → transparent
Complete sentence: The newest fibre optic cables that carry telephone calls are made of glass so transparent that a piece 100 meters thick is clearer than a standard windowpane. The sentence compares the glass with a windowpane and says that even a piece 100 metres thick is clearer than it, so the glass must be extremely transparent.
| Word | Meaning | Example |
|---|---|---|
| (1) fragile | easily broken or damaged (it is about strength, while the sentence is about how clear the glass is) | Pack the fragile cups in plenty of paper. |
| (2) tangible | that can be touched, or real and definite (it does not describe how well light passes through something) | The new road has brought tangible benefits to the villagers. |
| (3) transparent (answer) | allowing light to pass through, so that objects behind can be seen distinctly | Fresh mountain water is so transparent that you can see every pebble on the bed. |
| (4) iridescent | showing bright rainbow colours that change with the angle of view (such glass would not be clearer than a windowpane) | The soap bubble had an iridescent surface. |