During the early years of hardwired NC, built-in diagnostic tools existed.
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举一反三
- The first primitive man known to have existed in China is ( ), who lived about 1.7 million years ago. ( ),who existed more than 600,000 years ago at Zhoukoudian, in the vicinity of modern Beijing, could walk upright, make and use simple tools, and make use of ( ) .
- Chinese had mastered the technology of smelting bronze approximately 5,000 years ago and iron tools came into use during the ___________.
- During the early years of Eastern Han Dynasty, the complete twenty four solar terms came into being.（ ）
- An important advance in the philosophy of NC of machine tools was the shift toward the use of controller units instead of computers in NC systems.
- The factory ________ last year, and that one was built many years ago. A: was built B: build C: built
内容
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A water power station __in the area several years ago. A: build B: built C: is built D: was built
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The magnificent museum is said _____ about a hundred years ago. A: to be built B: to have been built C: to have built D: to have being built
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In the early frontier, which existed before the Civil War of the 1860s, the main struggle was man against the____________.
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In the early years of the Republic of Ch...cities like ______ .
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These houses ……… by settlers many years ago. A: are maid B: were built C: built D: made