例句與造句

1. These forms are called furanoses and pyranoses, respectively  by analogy with furan and pyran, the simplest compounds with the same carbon-oxygen ring ( although they lack the double bonds of these two molecules ).
2. The reaction between C-1 and C-5 creates a molecule with a six-membered ring, called pyranose, after the cyclic ether pyran, the simplest molecule with the same carbon-oxygen ring.
3. It's difficult to find oxygen ring in a sentence. 用oxygen ring造句挺難的