[詞彙區別] on the contrary, in contrast, on the other hand 的用法區別
在學術英文寫作，常常會需要做兩個觀點的正反面比較，或是提出另外一種看法，有三個最常見的片語可供選擇：on the contrary，in contrast 與 on the other hand，但這三種片語容易混淆常常造成寫作者的困擾，以下老師提供每個片語的解釋和用法，給同學參考，希望對同學有幫助。
◆on the contrary: （恰恰相反、相反地）
Use “on the contrary” when you have just said or implied that something is not true and are going to say that the opposite is true.
When I first met him, I thought he was a modest and gentle person. On the contrary, he is arrogant and ruthless.
A: I hear you enjoy running.
B: On the contrary, I find it to be tiresome.
◆in contrast, by contrast: （對照之下）
We use in contrast and, less commonly, by contrast to link two clauses. In contrast and by contrast stress the difference between two people or things more strongly than in comparison and by comparison. Some say that by contrast stresses comparison (比較) and in contrast stresses difference (差異). However, if I were to stress comparison, I would just use “in comparison."
Look for more examples here: https://dictionary.cambridge.org/zht/%E8%AA%9E%E6%B3%95/%E8%8B%B1%E5%BC%8F%E8%AA%9E%E6%B3%95/contrasts
In contrast and by contrast
We use in contrast and, less commonly, by contrast to link two clauses. In contrast and by contrast stress the difference between two people or things more strongly than in comparison and by comparison:
Holistic medicine treats the whole person. Conventional medicine, in contrast, treats specific symptoms and parts of the body.
We can use in contrast to or, less commonly, in contrast with to contrast two noun phrases:
In contrast to most of the city’s museums, the art museum is modern, bright and has a friendly atmosphere.
The white roses looked lovely in contrast with the red ones.
By contrast is less common than in contrast. We can use it alone or followed by with, but not by to:
In the south much of the land is flat. By contrast, in the north there are hills and mountains everywhere.
By contrast with the external appearance of the place, the room into which the front door opened was, if not particularly attractive, clean and well ordered.
◆on the other hand: （另一方面）
Use “on the one hand” to introduce the first of two contrasting points, facts, or ways of looking at something. It is always followed later by on the other hand or on the other.
The writing class is taking up too much of my time; on the other hand, I’m learning a lot about writing.
I hate working in a clothing store, but on the other hand, there are also some advantages.
總結來說，在寫文章的時候，如果你已經預設了立場，要表達與之前的說法相反或強調之前的說法是錯誤的，可以用 on the contrary。若要做客觀的觀點對比，不加入個人對錯想法，只是單純比較時就用 by contrast 或 in contrast (to/with)。而 on the other hand 則是說明一件事情的兩面，或是不同的看法，雖有部分人士認為此片語不夠正式，但在學術語料庫出現的頻率可是這三個裡面最高的。