Stemming is the process of finding the constant part of a word, which is the fragment that stays the same no matter which word tense or mode is used.
确定词干是查找单词中不变部分的过程，它是单词中与时态和语气无关的保持不变的片断。
2
Yet another great way of relaxing is an exercise where you tense each muscle in your body, one body part at a time, and then let the tensed muscle relax.
另一个很妙的放松方法就是锻炼。锻炼能拉紧你的每块肌肉，每次锻炼身体的一部分，然后让紧绷的肌肉放松。
3
The second part is a review of the studies on tense as a grammatical category.