Noun may be compared for exact or general SIMILARITY or DIFFERENCE. They may be also compared for similar or different QUALITIES or DEGREES, more or less, or specific qualities. In addition, they may be compared to ESTIMATES.
99. Comparative estimates - "more than" and "less than".
"More than" or "less than" is used before a specific numbers to express an estimate that may be a little more or a little less that the number.
more/less + than + number
There are more than three hundred streets in this city.
He has less than ten coins in his pocket.
Don't use "more" or "less" without "than" in estimates; Don't use "as" instead of "than".
100. Comparative estimates - "as many as".
"As many as" is used before a specific numbers to express an estimate that doesn't exceed the number.
as many as + number
He has as many as three cars now.
As many as five thousand students attend the summer school.
Don't use "as many" instead of "as many as"; Don't use "much" instead of "many" before specific numbers.
101. Degrees of comparison - comparative adjectives.
Two- and three-syllable adjectives form the comparative by using "more" or "less" before the adjective form. One-syllable adjectives form the comparative by adding "-er" after the form. Two-syllable adjectives ending in "y" form the comparative by changing "y" -> "i" and adding "-er"
difficult -> more difficult
hard -> harder
heavy -> heavier
comparative + than
This exam is more difficult than that.
This exam is harder than that.
This exam is easier than that.
Don't use "that" or "as" instead of "than"; Never use both "more" and "-er".
102. Degrees of comparison - superlative adjectives.
Superlatives are used to compare more than two.
super.
difficult -> most difficult
hard -> hardest
heavy -> heaviest
the + superlative
This exam is the most difficult that.
This exam is the hardest that.
This exam is the easiest that.
Don't use a comparative ("more" or "-er") form when three or more are compared.
