Definition
Used to describe two people or things that are completely different from each other.
截然不同
Although they are twins, their personalities are like chalk and cheese.
虽然他们是双胞胎，但他们的性格截然不同。
These two companies are like chalk and cheese when it comes to their business philosophies.
这两家公司在商业理念上截然不同。
I love outdoor activities, while she prefers to stay home and read; we are like chalk and cheese.
我喜欢户外活动，而她喜欢待在家里看书；我们截然不同。