What Is Their Main Difference?
Modal Verb Could
Here, we are requesting something.
Here, we are talking about past abilities.
Modal Verb Should
We use 'could' and 'should' to give advice.
'Could' is used to express our disapproval of something that has already happened in the past.
'Should' is used to express our thoughts on an event that may be happening now or will happen in the future.
Take a look at the following examples:
We use 'should' and 'could' to show something is likely or expected to happen. For example:
Negation and Question
To make sentences with modal verbs negative, we add 'not' to them as shown below:
- Could → Could not → Couldn't
- Should → Should not → Shouldn't
Here are some examples of negative sentences with 'should' and 'could:'
When creating interrogative forms, we simply invert the modal verbs. Watch:
With Other Modals
We can use modal verbs with other verbs but we cannot have more than one modal verb. Take a look at these incorrect examples:
shall could swim.
should would leave.
'Could' and 'should' are modal verbs that can also be used as conditional verbs in conditional mood.
|Conditional Type 1||✓||✓|
|Conditional Type 2||✓||✓|
|Conditional Type 3||✓||✗|
Conditional Type 1
Conditional Type 1 is used to talk about real situations. These situations are considered to have a high chance of occurrence. For examples:
If your dad calls, you
Conditional Type 2
Conditional Type 2 talks about hypothetical situations that are imaginary and their chance of occurrence are unlikely. These situations are in the present or the future. For instance:
If you win a lottery, you
If you win a lottery, you
Conditional Type 3
The third type of conditionals talks about the past. In this type, we are talking about an imaginary past that could have happened but it never did. In other words, we are imagining a different past. We can use 'could' in this type of conditional.
If I had practiced harder, I
We use 'could' to talk about abilities, talents, or skills that we had in the past but we no longer have them or stopped practicing them or the person who possessed the talent is deceased. Have a look:
Expressing an order
'Should' is used to express a not so strong and polite order, obligation, or instruction. We use it to politely tell other what to do and what not to do. For example:
'Could' is used to make not so definite suggestions. The receiver may or may not accept the offer. Here are some examples for clarity:
Future Predictions and Expectations
We use 'should' to predict and estimate a future event. We also use it to express our expectations about a situation. Look at these example:
Here, we are expressing expectations.
Here, we are predicting a future event.