Cool MateThey certainly do vs They do
When to use each in English, with meaning, register, and examples.
They certainly do
Top 5,000 (fairly common)
They do
Top 1,000 (very common)
Most common: They do
| They certainly do | They do | |
|---|---|---|
| Pronunciation | 🇬🇧 //ðeɪ ˈsɜːtənli duː//🇺🇸 //ðeɪ ˈsɜrtənli du// | 🇬🇧 //ðeɪ duː//🇺🇸 //ðeɪ du// |
| Meaning | They really do something. | A phrase used to express agreement or confirmation. |
| Example | If you think they are friendly, they certainly do seem that way. | When asked if they study hard, she said, 'They do.' |
| Register | Neutral | Neutral |
| How common | Top 5,000 (fairly common) | Top 1,000 (very common) |
| Collocations | do say, do believe, do enjoy | they do believe, they do care, they do listen |
| Common mistakes | Confused with 'they certainly don't' which has an opposite meaning., Using it in overly formal contexts where a simple 'yes' is more appropriate. | 'They do' is sometimes confused with 'They doesn't.', 'They do' may be misused in questions instead of answers., 'They do' can be incorrectly emphasized in writing. |
| Usage notes | Use this phrase to affirm or emphasize something that has been said. It's more emphatic than just saying 'yes'. Suitable for conversations but not very formal writing. | Commonly used in casual conversations to confirm or agree with a statement. Can be informal in tone. |
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Frequently asked questions: They certainly do vs They do
What's the difference between They certainly do and They do?
They certainly do: They really do something. They do: A phrase used to express agreement or confirmation.
Which is more common: They certainly do and They do?
They do is the most common in everyday English.
Can you show an example of each?
They certainly do: If you think they are friendly, they certainly do seem that way. They do: When asked if they study hard, she said, 'They do.'
Can I use They certainly do and They do interchangeably?
Not always. They certainly do and They do are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.