Do and would have different uses. Nonetheless, many ESL students are confused about them.
Do
Do and does are primary auxiliary verbs used in the simple present tense. We have already learned that the simple present tense is used to talk about general truths, facts, habits and routines. Since this tense form is made without an auxiliary verb, we use do and does to form questions and negatives.
- He knows the answer.
- He doesn’t know the answer.
- Does he know the answer?
- He makes delicious cookies.
- He doesn’t make delicious cookies.
- Does he make cookies?
- He has a car.
- He doesn’t have a car.
As you can see, these are all simple statements of fact.
Would
Would is a modal auxiliary verb. It is the past tense of will in reported speech.
- ‘I will come with you.’ she said.
- She said that she would come with me.
Would can also be used to talk about imaginary situations. Note that when we use would to talk about an imaginary situation, we usually use it with have + past participle.
- There was no point asking him, he wouldn’t have known the answer.
Would is used to indicate less possibility in Type 2 Conditional Sentences.
- If you asked her more politely, she would help.
Here we are not talking about an imaginary situation. Here the situation is real and possible but the chances of it happening are pretty low.
If you believe that something is likely to happen, you will use will, not would.
- If you ask her more politely, she will help.