either 两个中的一个
经常用either...or...
可以连接词和词或句子和句子
例子：you can choose ethier red or blue
either he went to the market,or he stay at home
also 也
放实意动词前
例子：i also play the piano
放be动词或助动词后
例子：i was also a dancer
i have also brought some candy
放句首
例子：also,i went to the party
不放句尾
or 或
连接词和词或句子和句子
例子：i can go swimming or runing
i can go to swim or to run
i can go shopping ot i can join the party
too 也
放句尾
例子：i like her,too.