表示「對比」的連接詞一般放在大作文的段落中間或者末尾，用來作為兩個東西的比較。
常用的一般就是by contrast, in contrast。這兩個表達可以替換。
Young people are keen to adopt new technology. In contrast, old people are cautious about the importance of technology to their work or business. (√)
要點一的句子可以用by comparision, in comparison進行替換，意思區別不大。雖然in contrast 一般來說前後對比的兩個事情差異性比較大，而by comparision 則未必。
Young people are sometimes fond of contact sport. By comparison, older people like gentle exercise. (√)
有同學喜歡用while，大家要注意這是一個連詞，而不是連接詞。
Young people are keen to adopt new technology, while old people are cautious about the importance of technology to their work or business. (√)
Young people are keen to adopt new technology. While, old people are cautious about the importance of technology to their work or business. (X)
使用however，nevertheless不是很恰當，因為這兩個一般是表示某個東西自己的轉折，而不是對比；此外，這兩個詞都屬於強轉折的副詞，用在段落中不是很好。
Young people are keen to adopt new technology. However, technology may not always be helpful. (√)
on the other hand和however差不多，只是on the other hand是弱轉折。On the other hand也不是用於兩個東西的對比和比較，經常用於說一個對象的兩方面。
Young people are keen to adopt new technology. On the other hand, they sometimes make rash decisions. (√)
有時候可以用compared to, compared with, in contrast to，但是後面要加名詞。
Compared with young people, older people are not very enthusiastic about new technology. (√)
on the contrary 只能用在前面句子出現否定的時候。
Young peopleare not interested in traditional ways of working. On the contrary, they arealways keen to change or reform the system. (√)
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