3D打印技术发展迅速，许多专家建议把这项技术介绍给更多的中学生．
The 3﹣D printing is developing fast．Manyexperts suggestthat it should be to more middle school students．
相关试题
（clean，tomorrow） 
（run，fast）． The stones in the park are different in （size/shape）．Some are round and some are square．
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