For thousands of years, people thought of glass as something beautiful to look at. Only recently (1) come to (2) something to look through. Stores (3) their goods in large glass windows. Glass bottles and jars (4) food and drink allow us (5) the contents. Glass (6) spectacles (眼镜), microscopes, telescopes, and (7) very useful and necessary objects. (8) are used by people who cannot see (9) or by people who want to protect their eyes (10) bright light. Microscopes make tiny things larger (11) we can examine them. Telescopes (12) objects that are far away appear (13) closer to us.
(14) in recent years plastics have replaced glass (15) conditions where glass might be (16) broken there are new uses (17) for glass that were never imagined in the (18) . Perhaps the greatest (19) . of glass is that its constituent (形成的) parts are inexpensive and can be found (20) over the world.

A．let

B．watch

C．get

D．make