2. In plain carbon steel, carbon is the only alloy element. 只有在普碳钢中，碳才是唯一的合金元素。
3. She painfully explained her complaint about the plain chain. 她痛苦地解释了她对朴素链条的抱怨。
英英解释
n.
1. extensive tract of level open land
2. a basic knitting stitch v.
1. express complaints, discontent, displeasure, or unhappiness
2. clearly revealed to the mind or the senses or judgment
3. not elaborate or elaborated; simple
4. lacking patterns especially in color
5. not mixed with extraneous elements
6. free from any effort to soften to disguise
7. lacking embellishment or ornamentation
8. lacking in physical beauty or proportion adv.
1. unmistakably (`plain' is often used informally for `plainly')
