爱思英语编者按：say和tell算是一对同义词，都表达“说”的意思。常常有同学分不清在哪些情况下该用say，哪些情况用tell，今天就来重点区分一下。

Say or Tell?

1. Say and Tell have no difference in meaning in this context except for the structure of the sentence.

You SAY something
“He said that he would be back at 3pm”.

You TELL someone something
“He told me that he would be back at 3pm”.

2. Use SAY when you’re quoting someone or with ‘thank you’, ‘sorry’ and ‘hi’.

“Johnny, say thank you to the lady for giving you the ice cream”.

“Say hi to Tom when you see him later”.

“Silvia says sorry for not getting back to you earlier. She has been so busy with work”

3. Use TELL when giving/asking for information or asking for instructions

“Could you tell me the time?” ( information)

“Can you tell me the quickest way to the railway station?” (instructions)

“Could you tell me when the next sales meeting will be?” (information)

“Hold on, I need to tell you something“ (information)

“Can you tell me how to work this computer?” (instructions)

4. We use TELL when we recognise signs

A: “You’ve been in the sun, haven’t you?
B:  How did you know?
A:  I can tell by your tan.

A: You’re from the UK, aren’t you?
B: How can you tell?
A: I can tell by your accent.

A: How can you tell you’re in love?
B: Mmm, let me think about that.

5. TELL – Special Expressions
We normally tell someone something. However, there are special expressions where we don’t have to tell someone. Here they are:

a. Tell a story or tell a joke 
You can tell a story (or you can tell me a story)

“I love telling jokes with my friends”
“Tell me a story”
“My family always tell stories around dinner table”.

b. Tell the truth or a lie
You can tell the truth and the whole truth (or you can tell me the truth and the whole truth)

“He has told so many lies in his career”
“I want you to tell me the truth for once”.

c. Tell Secrets
You can tell someone a secret or you can tell secrets

“He loves telling secrets”
“Can I tell you secret?

d. Tell the difference or tell things apart
You can tell someone the difference but you cannot tell someone things apart

“Can you tell me the difference between these two shirts?”
“Can you tell the difference between these two shirts?”
“I can’t tell the twins apart“