English and ESL Instructor
George is taller than Michael. (Compares George and Michael)
This new sponge is more absorbent than the old one. (Compares the new sponge to the old one)
Note that for comparatives where the suffix -er is added to an adjective, there is grammatically incorrect to add more in front, as is the case in the first example. The reason it is because a word like taller by itself already means more tall, which makes it unnecessary to put more in front. As such, the following example would be grammatically incorrect:
Jenny is more older than Annie.
The way we correct this would be to simply take out the more in the sentence:
Jenny is older than Annie.