I am unable to understand the meaning and correct usage of the above two sentences. Can anyone please explain their differences in meaning and usage?
Learn English – the difference between “How to know?” and “How to know?”
conditional-constructionsdifferencemodal-verbsrhetorical-questionssentence-meaning
Related Solutions
The quick answer: In most contexts, these two words are effectively synonyms, especially when discussing possibility, e.g. "(Can/Could) you [perform some action]?".
Longer answer:
There is a somewhat subtle difference in these two phrases that becomes a lot less subtle in different contexts. Let's take the words one at a time:
Can deals with actual, literal ability to perform an action. When you ask if someone can explain something, you are literally asking whether they are capable of explaining it. Edit: It is important to note that, as @J.R. has pointed out, this is by no means the only use (or even the most common use) of the word can or the phrase can you .... This construction is often abused to mean effectively the same thing as could you..., i.e. would you be willing to..., etc.
Could deals with the possibility of performing an action. It is definitely a subtle difference, but basically, when you discuss possibility, you generally are aware of their ability to do it but are tentative about their willingness or availability to perform the action. This is by no means an exact definition.
It is also worth noting that the word could is actually the past tense of can. In English, using the past tense form of a word in this way is often meant to indicate tentativeness.
I wanted to talk with you.
I wondered if you would be available this afternoon.
I thought it might a good idea.
A very thoughtful and hard question indeed; it pushed me to research a bit on the subject Continuous Conditional.
Your first example is a past perfect continuous sentence. In general, it is used to indicate an action was happening before another action happened. However, it can also be used to indicate past unreal condition. For example:
If I had been talking to him when he said that, I would have punched him in the face.
But fortunately, he was not talking to him when he said that and that's how he missed my punch.
So according to this theory, your first sentence which is
If I had been with you, I might be taking care.
is absolutely meaningful and grammatical.
Now, there is a vital fact when using these type of constructs as described by data.grammarbook.com,
When talking about something that didn’t happen in the past, many English speakers use the conditional perfect (if I would have done) when they should be using the past perfect (if I had done).
For example, you find out that your brother saw a movie yesterday. You would have liked to see it too, but you hadn’t known he was going. To express this, you can use an if – then clause. The correct way to say this is with the past perfect in the “if” clause, and the conditional perfect in the “then” clause:
Correct: If I had known that you were going to the movies, [then] I would have gone too.
The conditional perfect can only go in the “then” clause — it is grammatically incorrect to use the conditional perfect in the “if” clause:
Incorrect: If I would have known that you were going to the movies, I would have gone too.
More examples:
Correct: If I had gotten paid, we could have traveled together.
Incorrect: If I would have gotten paid, we could have traveled together.
Correct: If you had asked me, I could have helped you.
Incorrect: If you would have asked me, I could have helped you.
The same mistake occurs with the verb “wish.” You can’t use the conditional perfect when wishing something had happened; you again need the past perfect.
Correct: I wish I had known.
Incorrect: I wish I would have known.
Correct: I wish you had told me.
Incorrect: I wish you would have told me.
Correct: We wish they had been honest.
Incorrect: We wish they would have been honest.
So this theory, in a nutshell, says you can't use "would" part with the "if" clause, rather it should be used in the result clause. So, according to this theory, your second sentence stands incorrect.
Best Answer
There's no strict rule distinguishing them. Below, I'll explain the differences between what each question suggests and the situations where it's most appropriate.
How do I know?
"How do I know?" usually casts doubt on something that previously was assumed to be true. For example, if someone you've never heard of on the Internet asks you to send them US$1,200, after which they will send you information about a huge inheritance that you are owed, you might say:
Or, about almost any answer on ELL:
It's also used in sophomoric philosophy:
The point is to challenge an assumed proposition by asking for justification. One could answer by providing justification for the proposition in question.
How would I know?
"How would I know?" asks for a method of finding something out if a given proposition is true: something to check for. The word would indicates the conditional mood, suggesting that the question is about a hypothetical situation rather than a current one.
However, people also use the conditional mood as a polite "softener". "How do I know?" is quite challenging. It suggests that something has been carelessly or foolishly assumed. So, someone might ask "How would I know?" even about a present situation, in order to avoid sounding challenging.
Also, you might say "How would I know?" about a present situation if the matter in question is simply unknown:
In this sense, you could also say "How can I tell?" or "How could I tell?" The conditional mood suggests that you are temporarily assuming the part after "if" as a hypothesis. For example, "If this car were stolen, how would I know?" or "If this car were stolen, how could I tell?"
With something unknown but not hypothetical, you would more likely say "How can I tell?" or "How do I know?" For example:
Since it is known that you are running Safari, there is no hypothesis to base a condition on. But you could also express it as "How could I tell which version…?" (or "How would I know…?"); in this case, the implied hypothesis is "If I were going to find out which version…"
Other uses
These questions have other uses, too. "How would I know … without …?" suggests that you could not know something without the indicated test:
You can say "How would I know?" as a rhetorical question, to mean that you couldn't possibly know the matter in question, or that there is no answer that could be known:
You can't say "How do I know?" in this sense. The conditional mood is necessary because the question is based on an implied hypothesis which you are saying is false: you are implying that you don't know and can't know.