adj.extremely important and necessary必不可少的，非常重要的 I)You can survive without food for some time,but water is essential. II)It is essential that our pilots be given the best possible training. 词组短语 essential condition必要条件 essential difference本质区别 essential qualities固有性；本质(essential quality的复数) be essential for对.必不可少的 essential goods主要货物；必需品 同近义词 adj基本的；必要的；本质的；精华的elementary,fundamental,basic,necessary,primary n本质；要素；要点：必需品 element,necessity 同根词 词根：essence adv. essentially本质上；本来 essence本质，实质；精华；香精 essentiality重要性；本质；真髓；根本性 7.expand (Line5,Para5) 用法： v.become larger in size,number,,or amount,or make sth.dothis(使)扩大，（使）扩展 I)The population of the town expanded rapidly in the 1960s. II)As children grow older they expand their interests and become more confident. 词组短语 expand market开拓市场 expand into扩大为 expand domestic demand扩大内需 同近义词 vt.扩张；使膨胀；详述enlarge on vi发展；张开，展开grow 同根词 词根：expand adj. expanded扩充的；展开的 expansive广阔的；扩张的；豪爽的 expandable可膨胀的；可张开的 expansible能扩张的；会膨胀的 adv. expansively辽阔地；可扩张地 n. expansion膨胀；阐述；扩张物 expanse宽阔；广阔的区域；苍天；膨胀扩张 88 adj. extremely important and necessary 必不可少的，非常重要的 I) You can survive without food for some time, but water is essential. II) It is essential that our pilots be given the best possible training. 词组短语 essential condition 必要条件 essential difference 本质区别 essential qualities 固有性；本质（essential quality 的复数） be essential for 对…必不可少的 essential goods 主要货物；必需品 同近义词 adj.基本的；必要的；本质的；精华的 elementary, fundamental, basic, necessary, primary n.本质；要素；要点；必需品 element, necessity 同根词 词根：essence adv. essentially 本质上；本来 n. essence 本质，实质；精华；香精 essentiality 重要性；本质；真髓；根本性 7. expand (Line5,Para5) 用法： v. become larger in size, number, or amount, or make sth. do this （使）扩大，（使）扩展 I) The population of the town expanded rapidly in the 1960s. II) As children grow older they expand their interests and become more confident. 词组短语 expand market 开拓市场 expand into 扩大为 expand domestic demand 扩大内需 同近义词 vt.扩张；使膨胀；详述 enlarge on vi.发展；张开，展开 grow 同根词 词根：expand adj. expanded 扩充的；展开的 expansive 广阔的；扩张的；豪爽的 expandable 可膨胀的；可张开的 expansible 能扩张的；会膨胀的 adv. expansively 辽阔地；可扩张地 n. expansion 膨胀；阐述；扩张物 expanse 宽阔；广阔的区域；苍天；膨胀扩张