What is the role of 'as' in comparative sentences?

In comparative sentences, the word 'as' plays the role of introducing the second element being compared and indicating that the two elements are being compared on an equal level. It is used to show that the degree or level of a particular quality or characteristic in both elements is the same.

The word 'as' is commonly used in comparative sentences to form the structure "as + adjective/adverb + as." This structure is used to express that two things or people are equal in terms of a specific quality or characteristic. For example:

1. She is as tall as her sister.
In this sentence, 'as tall as' is used to compare the height of two sisters and indicates that they have the same level of height.

2. John runs as fast as Tom.
Here, 'as fast as' is used to compare the speed of John and Tom, suggesting that they both have the same level of speed.

3. This car is as expensive as that one.
In this example, 'as expensive as' is used to compare the prices of two cars, indicating that they have the same level of cost.

The use of 'as' in comparative sentences helps to establish an equal comparison between two elements. It emphasizes that both elements possess the same degree or level of the quality or characteristic being compared.