3.仔細分析可發(fā)現(xiàn)，第3、4句之間邏輯關(guān)系緊密，第4句句首的“這”指代的正是第3句中的內(nèi)容，故第4句可譯為which引導(dǎo)的非限制性定語從句。

　　4.最后一句中含有三個謂語動詞，“提供……機會”、“提高……生活水平”以及“豐富……體驗”，后兩者是“不但......也......”的并列結(jié)構(gòu)，可用not only... but also...來表達。而“提供......機會”可看作是“提高人們的生活水平”的方式故可用By引導(dǎo)介詞短語作狀語，表達為By offering better education and more jobopportunities。

　　參考譯文

　　Urbanization refers to the process of rural peoplemigrating into cities. A key index of a nation'surbanization level is the distribution of itspopulation in rural and urban areas. In the lastyear, the urbanization rate of China was over 50%,which marks that China has stepped into a new "city-based society". Urbanization has become an important part of China's social and economicdevelopment. By offering better education and more job opportunities to urban residents, itnot only improves their living standards, but also enriches their cultural experiences.