以下四种常用的流量计中测量精度较高的是（）

A.节流式流量计

B.容积式流量计

C.转子流量计

D.靶式流量计

Robots came into the world as a literary device whereby the writers and film-makers of the early 20th century could explore their hopes and fears about technology, as the era of the automobile, telephone and aeroplane picked up its reckless jazz-age speed. Since moving from the page and screen to real life, robots have been a mild disappointment. They do some things that humans cannot do themselves, like exploring Mars, and a host of things people do not much want to do, like dealing with unexploded bombs or vacuuming floors. And they are very useful in bits of manufacturing.　　But reliable robots-especially ones required to work beyond the safety cages of a factory floor—have proved hard to make, and robots are still pretty stupid. So although they fascinate people, they have not yet made much of a mark on the world. That seems about to change. The dramatic growth in the power of silicon chips, digital sensors and high bandwidth communications improves robots just as it improves all sorts of other products.