1.當表示“相似”時，多用as，避免使用that。
She has the same fair hair and blue eyes as her mother had.
她和母親一樣有著同樣的金色頭發和藍色眼睛。（as做had的賓語）
This coffee is the same as we had at Mrs.Dawson’s.
這咖啡和我們在道森婦人家喝的一樣。
His hair’s the same colour as her mother’s.
她的頭發和母親的頭發是同樣的顏色。（mother’s后面省略了is，所用as作表語）
2.當表示“同一”時，多用that，但也可以用as。
He works in the same shop（that/as）I do.
他和我在同一家商店工作。（as/that作賓語）
I went out the same way（that）I’d got in.
我順著進來的原路出去的。（that作狀語，表方式）
We rode the same way as we had come out the evening before.
我們乘車行駛在前一天晚上出來的同一條路上。（as作狀語，表方式）
（4）Meet me at the same place as you did yesterday.
請到昨天見我的那個地方來見我。（as作地點狀語）
3.定語從句為省略結構，要用as不用that。
I read the same book as you.
我和你讀的書是一樣的。（as表示相似）
He gave the same answer as before.
他給的答案和以前的相同。（as表示同一）
She lives in the same house as her husband.
她和丈夫住在一個房子里。（as表示同一）
4.the same后沒有被修飾的名詞也沒有暗含一個one時，只能用as而不用that。
I feel the same today as I did yesterday.（today在這里是副詞作狀語）
5.that作賓語可以省略而as不可以。
She is the same girl that I sat next to last year.
她和去年坐在我旁邊的那個女孩是同一個人。
I live in the same house as he lives in.
我和他住在同一個屋。