1.deficiency n．缺陷(absence of sth. essential; incompleteness)；不足(shortage)

词根记忆：de+fic(做)+iency--没做好--缺陷

例:Persons who suffer from a deficiency of the blood enzyme G6PD discover that eating fava beanS triggers hemolytic anemia.

同根词：deficient(a.不足的；有缺陷的)

2.deficit n.赤字(an excess of expenditure over revenue)

例:A shrinking trade deficit actually added l.57% to GDP this quarter.

派生词：deficiency(n.缺乏，不足)

3.definition n.定义(a statement expressing the essential nature of sth.)

词根记忆：来自definite(a.一定的；确切的)

例:A more precise definition of the term "small firm' is crucial to making a conclusive analysis about small firms' roles.

同根词：definitive(a．确定的；权威性的;n.限定词)

4.definitive a．确定的(conclusive)；权威性的( authoritative)

词根记忆：de(加强)+fin(结束)+itiVe(…的)--最终拍板的一权威性的

例:While raising important questions, Eisenstein's essays do not provide definitive answers.

5.deflect v.（使）偏斜,（使）转舟(to turn aside, deviate)

联想记忆：de(离开)+flect(弯曲--弯到旁边--偏斜

例:With no electric charge,a neutrino can cross the entire universe without being absorbed or even deflrected.

6.deform v.使变形(to arter the shape by stress)

词根记忆：de(表否定)+form（形状）--使不再是原来的形状一使变形

例:The stress is severe enough to deform it like putty.

派生词:deformation(n.变形)

7.defrost v.除霜(to free from ice);解冻(to release from a frozen state)

词根记忆：de(去掉)+frost(霜)--去除霜--除霜;解冻

例:No attempt was made to defrost the back window.

8.degradation n.退化;降级(decline to a low, destitute, or demoralized state);重落(moral or intellectual decadence)

词根记忆：来自degrade(v.贬低;降级;退化)

例:Indeed, most analysts believe that some kind of environmental degradation underlies the demise of many extinct salmon populations.

9.degrade n.降低…的身份(to demote)；（使）降解(to decompose)；（使）退化(to decompose)

词根记忆：de（去掉）+grade(级别)--去掉级别--降低…的身份

例:They argued that the technique had degraded works of art.

10.dehydrate v.（使）脱水(to remove water from; to lose water)

词根记忆：de(去掉)+hydr(水)+ated--去水的--脱水

例:Retail prices of dehydrated potatoes have declined.

派生词：dehydration(n.脱水)