Comparing and contrasting

To compare two things, show what they share: both… and…, similarly, likewise, like. To contrast them, show how they differ: whereas, while, on the other hand, unlike.

Whereas and while join two clauses in one sentence: Trains are fast, whereas buses are cheap. On the other hand starts a new sentence and takes a comma: Trains are fast. On the other hand, they are expensive.

Unlike and like come before a noun: unlike buses, trains rarely get stuck in traffic. Write comparatives correctly: cheaper than, more comfortable than, never more cheaper.