One: Interpretation of meaning
English [k] ok? n，k？ n]？ Beauty [k? n，k？ n]？
Modality (indicating the ability to do or happen) can, will Yes, you can; Metal jar (used to hold food or drink);
Is English ok? d，k？ d]？ Beauty [k? d，k？ d]？
Modality energy, will; (Asking if something can be done) Yes, yes?
Similarity: both can mean "yes, yes"
Difference: theoretically, could is the past tense of can, but in some cases, it can also mean the present or even the future, not the past.
Two: the difference in usage
Can and could are used differently:
1, indicating current ability or general ability, using can instead of could. You usually don't use can or could, but the future tense of able to. But if you decide now whether you can do something in the future, it is available. Sure.
2, said the past ability, sometimes you can use it, sometimes you can't use it. When using the past general ability, you need to pay attention, that is, the ability to do something at any time in the past can be used at this time.
3. If you express your past specific ability, that is, the ability to do something in the past specific circumstances, you can't use could, but you can use was(were)capable to do sth instead. In negative sentences, it can't be used to express past specific abilities.
4. When followed by sensory verbs see see, hear, taste, feel, smell, understand, sensory, guess, etc. Can be used to express someone's ability to do something in a specific situation in the past. In indirect speech, could can also indicate a specific ability in the past.
Three: Typical examples
1, yes
-when? Is it okay? Me? Get? Mine? Testing? The result?
When can I get the test results?
-We? Is it okay? Reduce? That? Question? Where to? Two? Mainly? problem
We can reduce this problem to two main points.
-I will? Do you see it? What? Me? Is it okay? Do what? Where to? Help!
I'll think about it and see what I can do.
2. Is that all right?
-We? Is it okay? Do you hear me? Sound? Yes? Revelry? From where? Next? Doors.
We can hear the sound of binge drinking next door.
-She? Confused? She? A critic? And then what? Proved it? She? Is it okay? Do what? That? Work.
She refuted her critics and proved that she was qualified for the job.
-me? Think? we? Is it okay? All of them? Use? Answer? Drink? After that? That!
I think we should all have a good drink after we finish.