1.谓语动词三单形式（第三人称单数形式）的变化规则:
(1)一般情况下，直接加“s”；
e.g.help—helps
like—likes
come—comes
play—plays
find—finds
(2)以s, x, sh, ch, o结尾的动词，加“es”；
e.g. guess—guesses
fix—fixes
teach—teaches
finish—finishes
go—goes
do—does
(3)以辅音字母加“y”结尾的动词，变“y”为“i”，再加“es”。
e.g. study—studies
worry—worries
try—tries
carry—carries
2.可数名词单复数变化规则：
(1)通常情况下，直接加“s”；
e.g. student—students
book—books
tree—trees
(2)以s, x, ch, sh结尾的名词加“es”；
e.g. glass—glasses
box—boxes
brush—brushes
match—matches
(3)以辅音字母加“y”结尾的名词，变“y”为“i”加“es”；
e.g. city—cities
baby—babies
enemy—enemies
(4)以“f”或“fe”结尾的名词，多数变“f”或“fe”为“v”加“es”(注意：roof, chief 加s)；
e.g. wife—wives
knife—knives
leaf—leaves
(5)以“o”结尾的名词，有的加“es”(hero, tomato, potato, echo);有的加“s”（radio, kilo, auto, zoo, piano, photo, bamboo）。有生命的加“es”，无生命的加“s”;
(6)常见不规则变法名词：
e.g. foot—feet
goose—geese
tooth—teeth
child—children
man—men
woman—women
sheep—sheep
deer—deer
mouse—mice
medium—media
datum—data
bacterium—bacteria
phenomenon—phenomena
basis—bases
fish—fish
shark—shark
3.动词-ing形式的变化过则：
(1)一般情况下，直接加-ing;
e.g. go—going
ask —asking
look—looking
carry—carrying
(2)以不发音的e结尾的动词，去e加-ing;
e.g. write—writing
make—making
take—taking
move—moving
live—living
leave—leaving
(3)以重读闭音节(一个辅音加一个元音)结尾的动词，末尾只有一个辅音字母，双写这个辅音字母，再加-ing；
e.g. get—getting
sit—sitting
put—putting
run—running
begin—beginning
plan—planning
cut—cutting
get—getting
beg—begging
(4)注意（特殊）：
die—dying
lie—lying
tie—tying
picnic—picnicking
panic—panicking
listen—listening
develop—developing
4.动词过去式（过去分词）的转化规则:
(1)规则动词的转化规则：
①一般情况下直接加ed；
e.g. look—looked
play—played
start—started
②以e结尾的动词加d；
e.g. live—lived
hope—hoped
use—used
face—aced
③以重读闭音节结尾的，末尾只有一个辅音字母的，双写这个辅音字母，再加ed；
e.g. stop—stopped
plan—planned
permit—permitted
beg—begged
④以辅音字母加y结尾的动词，变y为i再加ed；
e.g. study—studied
carry—carried
worry—worried
(2)不规则动词的变化规则：
①原形，过去式和过去分词形式相同：
e.g. hit—hit—hit
set—set—set
put—put—put
cut—cut—cut
cast—cast—cast
cost—cost—cost
shut—shut—shut
hurt—hurt—hurt
burst—burst—burst
spread—spread—spread
②过去式和过去分词同形：
e.g. feed—fed—fed
bleed—bled—bled
bend—bent—bent
buy—bought—bought
breed—bred—bred
fight—fought—fought
bring—brought—brought
catch—caught—caught
sell—sold—-sold
leave—left—left
meet—met—met
send—sent—sent
find—found—found
sleep—slept—slept
teach—taught—taught
think—thought—thought
③原形，过去式和过去分词均不相同：
e.g. lie—lay—lain
see—saw—seen
rise—rose—risen
give—gave—given
begin—began—begun
blow—blew—blown
know—knew—known
grow—grew—grown
break—broke—broken
drink—drank—drunk
speak—spoke—spoken
swim—swam—swum