1.dictate v.规定，支配(to impose, or specify authoritatively)

词根记忆：dict(说)+ate--规定

例:Capitalists who owned enough stock to dominate the board of directors always dictate company policy.

2.diesel n．内燃机，柴油机(a diesel engine)

词根记忆：由德国的发明家Diesel(狄赛尔)而来

派生词：diesel fuel柴油

3.dietary a．饮食的(of or relating to a diet or to the rules of a diet)

词根记忆：来自diet(n.饮食)

例:When maize was introduced into southern Europe, it quickly became a dietary staple.

4.differentiate v.区别(to mark or show a difference in)；【生】分化(to undergo a pro-gressive, developmental change to a more specialized form or function)

词根记忆：来自different(a．不同的)

例:Improved customer service is the best way for us to differentiate ourselves from competitors.,,The hormones will cause plant cells to differentiate to perform different functions.

5.differentiation n.变异（the act or process of differentiating）；分化;区别(a discrimination between things as different and distinct)

词根记忆：来自differentiate(v.区分)

例:While studying the genetic makeup of com, Barbara McClintock discovered a new class of mutant genes,a discovery that led to greater understanding of cell differentiation.

同根词：differentially(ad.区别地)

6.digest v.消化(to convert( food) into absorbable form);吸收( to absorb; to take into the mind or memory)n.摘要【a summation or condensation of a body of information)

词根记忆：di（向下）+gest(运)--将食物向下运--消化

例:If proteins are taken orally, they are digested and cannot reach their target cells.

派生词：digestion(n．消化力)：digestive(a．消化的)

7.digit n.数字(number)；【数】十位数

例:the tens digit

派生词：digitize(v.将…数字化)；digital(a．数字的)

8.digtize v.数字化(to convert( as data or an image) to digital form)

词根记忆：digit(数字)+ize--数字化

例:The sound emissions were digitized and analyzed on computers.

同根词：digital(a．数字的；手指的)

9.dilemma n.困境，左右为难（a problem involving a difficult choice）

发音记忆：“地雷嘛”--被陷雷区，进退两难--困境

例:The company solved its globalization dilemma effectively by forging alliances with the best foreign partners.

10.dilute v.冲淡，稀释(to make thinner or more liquid by admixture)

例:Those concentrated cleaning products must be diluted before using them.

派生词：dilution(n.稀释，渗水)