1. reduce [rɪ'djuːs] 
v. 减少，降低
A low-fat diet can reduce the risk ofheart disease. 低脂饮食可降低心脏病的风险。

2. decrease [dɪ'kriːs] 
v./n. 减少，减小
Our share of market has decreasedsharply this year. 今 年我们的市场份额急剧减少。

3. descend [dɪ'send] 
v. 下降，下去，遗传
Jane descended the stairs. 简下了楼梯。
descendant n. 后裔，子孙

4. diminish [dɪ'mɪnɪʃ] 
v. 减少，缩小
These memories will not be diminishedby time. 这些记忆不会因时间而减少。

5. decay [dɪ'keɪ] 
v. 衰退，腐烂，衰败
It’s sad to watch a beautiful rose towither and decay in such a short time. 看着一朵美丽的玫瑰花在这么短的时间里枯萎腐烂真是令人难过。

6. erode [ɪ'rəʊd] 
v. 侵蚀，腐蚀 
erosion n.
Wind and rain have eroded the statuesinto shapeless lumps of stone. 风雨侵蚀使雕像变成了一块块毫无形状的石头。

7. corrode [kə'rəʊd] 
v. 侵蚀，腐蚀 
corrosion n.
Rain water corroded the metal pipes. 雨水腐蚀了金属管子。

8. degenerate [dɪ'dʒen(ə)rət] 
v. 退化，堕落 adj. 堕落的，退化的 
a degenerate young man 堕落的年轻人

9. deteriorate [dɪ'tɪərɪəreɪt] 
v.恶化，变化
She went into the hospital when her conditionbegan to deteriorate. 她的状况开始恶化她才去了医院。

10. aggravate ['ægrəveɪt] 
v. 加重，使恶化，激怒
The treatment only aggravated the condition.治疗只是加重了他的病情。