一、形容詞、副詞的比較級和最高階的構成規則
1.一般單音節詞和少數以-er，-ow結尾的雙音節詞，比較級在後面加-er，最高階在後面加-est;
(1)單音節詞
如：small→smaller→smallest short→shorter→shortest
tall→taller→tallest great→greater→greatest
(2)雙音節詞
如：clever→cleverer→cleverest narrow→narrower→narrowest
2.以不發音e結尾的單音節詞，比較在原級後加-r，最高階在原級後加-st;
如：large→larger→largest nice→nicer→nicest able→abler→ablest
3.在重讀閉音節(即：子音+母音+子音)中，先雙寫末尾的子音字母，比較級加-er，最高階加-est;
如：big→bigger→biggest hot→hotter→hottest fat→fatter→fattest
4.以“子音字母+y”結尾的雙音節詞， 把y改為i，比較級加-er，最高階加-est;
如：easy→easier→easiest heavy→heavier→heaviest
busy→busier→busiest happy→happier→happiest
5.其他雙音節詞和多音節詞，比較級在前面加more，最高階在前面加most;
如：beautiful→more beautiful→most beautiful
different→more different→most different
easily→more easily→most easily
注意：(1)形容詞最高階前通常必須用定冠詞 the，副詞最高階前可不用。
例句： The Sahara is the biggest desert in the world.
(2) 形容詞most前面沒有the，不表示最高階的含義，只表示"非常"。
It is a most important problem.
=It is a very important problem.
6.有少數形容詞、副詞的比較級和最高階是不規則的，必須熟記。
如：good→better→best well→better→best
bad→worse→worst ill→worse→worst
old→older/elder→oldest/eldest
many/much→more→most little→less→least
far →further/farther→ furthest/farthest
二、形容詞、副詞的比較級和最高階的用法
1.“A + be +形容詞比較級 + than + B” 意思為“A比B更……”。
如：This tree is taller than that one. 這棵樹比那棵樹高。
注意：
① 在含有連詞than的比較級中，前後的比較物件必須是同一範疇，即同類事物之間的比較。
②在比較級前面使用much，表示程度程度“強得多”。
如：A watermelon is much bigger than an apple.
③ very, quite一般只能修飾原級，不能修飾比較級。
2.“比較級 + and + 比較級”或“more and more +原級”表示“越來越……”
如：It becomes warmer and warmer when spring comes.
春天來了，天氣變得越來越暖和了。
It is getting cooler and cooler.
天氣越來越涼爽。
The wind became more and more heavily.
風變得越來越大。
Our school is becoming more and more beautiful.
我們的學校變得越來越美麗。
3.在含有or的選擇疑問句中，如果有兩者供選擇，前面的形容詞要用比較級形式。
如：Who is taller,Tim or Tom? 誰更高，Tim還是Tom?
4. “the +比較級……, the+比較級”，表示“越……越……”。
The more money you make, the more you spend.
錢你賺得越多，花得越多。
The sooner，the better.
越快越好。
5. 表示倍數的比較級用法：
①. A is …times the size /height/length/width of B.
如：The new building is three times the height of the old one.
這座新樓比那座舊樓高三倍。(新樓是舊樓的四倍高)
②. A is …times as big /high/long/wide/large as B.
如：Asia is four times as large as Europe.
亞洲是歐洲的四倍大。(亞洲比歐洲大三倍)
③. A is …times larger /higher/longer/wider than B.
如：Our school is twice bigger than yours.
我們學校比你們學校大兩倍。
6.形容詞、副詞的最高階形式主要用來表示三者或三者以上人或事物的比較，表示“最……”的.意思。
句子中有表示範圍的詞或短語。如：of the three, in our class等等。
如：He is the tallest in our class.
他在我們班裡是最高的。
7."否定詞語+比較級"，"否定詞語+ so… as"結構表示最高階含義。
Nothing is so easy as this.
=Nothing is easier than this.
=This is the easiest thing.
8. 比較級與最高階的轉換：
Mike is the most intelligent in his class.
Mike is more intelligent than any other student in his class
7.修飾比較級和最高階的詞
1)可修飾比較級的詞
①.a bit, a little, rather, much, far, by far, many, a lot, lots, a great deal, any, still, even等。
②. 還可以用表示倍數的詞或度量名詞作修飾語。
③. 以上詞(除by far)外，必須置於比較級形容詞或副詞的前面。
注意： 使用最高階要注意將主語包括在比較範圍內。
(錯) Tom is the tallest of his three brothers.
(對) Tom is the tallest of the three brothers.
2)下列詞可修飾最高階：by far, far, much, mostly, almost。
This hat is nearly / almost the biggest.
注意：
a. very可修飾最高階，但位置與much不同。
This is the very best.
This is much the best.
b. 序數詞通常只修飾最高階。
Africa is the second largest continent.
8.要避免重複使用比較級。
(錯) He is more cleverer than his brother.
(對) He is more clever than his brother.
(對) He is cleverer than his brother.
9.要避免將主語含在比較物件中。
(錯) China is larger that any country in Asia.
(對) China is larger than any other country in Asia.
10.要注意對應句型，遵循前後一致的原則。
The population of Shanghai is larger than that of Beijing.
It is easier to make a plan than to carry it out.
11.要注意冠詞的使用，後有名詞的時候，前面才有可能有名詞。
比較：Which is larger, Canada or Australia?
Which is the larger country, Canada or Australia?
She is taller than her two sisters.
She is the taller of the two sisters.
