2018考研英語(yǔ)長(zhǎng)難句分析指導(dǎo)（三十八）

　　Dependence is marked first by an increased tolerance, with more and more of the substance required to produce the desired effect, and then by the appearance of unpleasant withdrawal symptoms when the substance is discontinued.

　　結(jié)構(gòu)分析：句子主干是Dependence is marked first by…, with…, and then by…。with引導(dǎo)的是伴隨結(jié)構(gòu)作狀語(yǔ)，修飾的是整個(gè)第一分句描述的狀態(tài)。and引導(dǎo)的分句省略了謂語(yǔ)動(dòng)詞marked ，所以該分句并不隸屬于第一分句，而是與之并列的結(jié)構(gòu)，when引導(dǎo)的是第二個(gè)分句的時(shí)間狀語(yǔ)從句。

　　譯文：依賴最初表現(xiàn)為忍耐力增強(qiáng)，用量越來(lái)越大才能達(dá)到預(yù)期效果，一旦停用就會(huì)產(chǎn)生不舒服的癥狀。