1、also 一般放在肯定句中，位置是在be动词、情态动词和助动词之后，实义动词之前，有时为了强调，也可以放在句首。
例如：He is also a good and healthy boy.他也是一个既善良又健康的男孩。
We can also go to the Tom's birthday party.我们也可以去参加汤姆的生日派对。
My friend has also had the chicken and salad.我的朋友也吃了鸡肉和沙拉。
You also need a pair of trousers in blue for school.你也需要一条上学穿的蓝色裤子。
Also, you must come to my home, of course.当然，你也必须来我家。
2、too常放在肯定句句末，前必须有“，”把它和前面的句子分开。
例如：Tina is a nice girl, and Jane is a nice girl, too.缇娜是一个漂亮的女孩。简也是一个漂亮的女孩。
My father can draw pictures well, me too.我爸爸画的画好，我也是。
3、either常用于否定句和疑问句中，前也必须有“，”，把它和前面的内容分开。
例如：I don't like math, my brother Bob doesn't like it, either, because we think it's so difficult.我不喜欢数学，我的兄弟鲍勃也不喜欢，因为我们都认为它学起来太难了。
Why don't you play tennis with your sister, either?为什么你也不和你的姐姐打网球呢？
4、as well 也常用于肯定句中，总是放在句末，但是前面不用“，”。
例如：My grandpa likes doing some kung fu, my grandma likes it as well.我爷爷喜欢练武术，我奶奶也是。
For breakfast, she has bread and milk, and I have them as well.早餐，他吃了面包和牛奶，我也是。
幸福、定格
