It is，everyone agrees，a huge task that the child performs when he learn to speak，and the fact that he does so in so short a period of time challenges explanation.

　　Do the constantly changing fashions of women's clothes，one wonders，reflect basic qualities of inconstancy and instability？

　　It was probably not until the 1880's that man，with the help of more advanced steam locomotive，managed to reach a speed of one hundred mph （英里）

　　要點(diǎn)分析和參考譯文

　　要點(diǎn)：“everyone agrees”為插入語(yǔ)�！癮nd”連結(jié)兩個(gè)并列句，前一句為“it is … that”強(qiáng)調(diào)句型；后一分句“the fact”后為同位語(yǔ)從句“that he does so in so short a period of time”，因此，后一分句的主要部分為the fact challenges（需要）explanation

　　參考譯文：每個(gè)人都同意孩子學(xué)說(shuō)話(huà)確實(shí)是件困難的事，并且孩子能在這么短的時(shí)間里做到的確需要很好的解釋才行。

　　要點(diǎn)：“one wonders”為插入語(yǔ)，本句主干結(jié)構(gòu)為“Do the fashions reflect qualities？”，“fashions” 有兩個(gè)定語(yǔ)“constantly changing”和“of women's clothes”。“qualities”也有兩個(gè)定語(yǔ)“basic”和“of inconstancy and instability”。

　　參考譯文：我們不知道女性服裝不斷變化的時(shí)尚是否反映出不可靠和不穩(wěn)定的基本特點(diǎn)。

　　要點(diǎn)：此句為強(qiáng)調(diào)句型“It was …that…”； that 從句中主語(yǔ)man和謂語(yǔ)managed 之間插入介詞短語(yǔ)“with the help of …”作狀語(yǔ)。