1. as…as 结构。该结构的意思是“与…一样”，其间应接形容词原级，不能用比较级或最高级。如：
He is as tall as his father. 他与他父亲一样高。
He is as busy as before. 他还是像以前那样忙。
在否定句中第一个as也可换成 so，其意为“不如”：
He is not as [so] tall as his father. 他不如他父亲高。
He is not as [so] busy as before. 他不像以前那样忙。
2. more and more与 the more…, the more…：前者表示“越来越……”，后者表示“越……，越……”。如：
Our country is getting more and more powerful. 我们国家越来越强大。
The more we get together, the happier we will be. 人聚得越多，我们越快活。
3. more than 与less than：前者“(指数量)多于”、“不只是”、“非常”等，后者表示“少于”、“比……少”。如：
I’ve known him for more than 10 years. 我已认识他10多年了。
He is more than a father to her. 他待她胜过父亲。
She was more than kind to us. 她对我们很友好。
It cost me less than 10 pounds. 我买它没要上10英镑。
She eats less than she should. 她吃得比她应该吃的少。
4. more …than 与 less…than：前者表示“比……多，比……更”，后者表示“比……少，不如……”。如：
He has more books than me. 他的书比我多。
He is more careful than the others. 他比其他人更仔细。
I got less money than the others did. 我比别人得到的钱少。
注：两者均可表示“与其……不如”，但词序不同。如：
He is less a teacher than an expert. / He is more an expert than a teacher. / He is not so much a teacher as an expert. 与其说他是老师，不如说他是专家。
5. “no+比较级+than”结构：这类结构的实际意思是对待比较的两个对象进行否定，相当于该原级形容词或副词使用as…as结构的意思。如no better than = as bad as，意为“与……一样不好”，no faster than = as slow as，意为“与……一样不快”，no taller than = as short as，意为“与……一样不高”等。
6. no more than与not more than：两者均可表示数量，前者表示“仅仅”、“只有”(= only)，强调少;而后者表示“不多于”、“至多”(= at most)。如：
It is no more than five miles to the station. 去车站只有5英里。
It is not more than five miles to the station. 去车站最多5英里。
