He never says a word unless he's being threatened in someway.
My question here is why the speaker used the form "is being threatened" and not "is threatened". When I should use the first form "is threatened" and not the second "is being threatened"? Is there a certain rule to follow?
You could use 'is threatened'. the effect of the progressive form, IMO, is to focus sharply on the particular circustances- so it adds more emphasis.
The trouble I am having with unreal/hypothetical conditionals is that sometimes I can't tell whether the sentence refers to a present/future real condition or to a present/future unreal condition. Is it a matter of the speaker's choice and his/her degree of certainty about the possibility of a situation-if it is likely or unlikely to happen?
Largely, yes- the British lottery was ordered to use unreal conditionals (It could be you) because a court determined that the real was unrealistic, but an optimist could buy a ticket and say 'if I win'.
If you help me now, you are a true friend.
If you helped me, you would be a true friend.
The first sentence makes a complete sense to me. It suggests that the speaker is somewhat sure that his/her friend is gonna help. Am I right there? The second sentence, however, indicates that the speaker doubts that his/her friend will lend a hand.
The second could always be seen as less hard sell- giving the friend the choice.
If they didn't show him the way, he will not find the right office.
If they don't show him the way, he will not find the right office.
If they didn't show him the way, he wouldn't find the right office.
The first sentence sounds fine (the guy has already asked for directions, but he will not find the right office unless the people he has asked them for directions have already showed him the way. Is my interpretation correct?
I'd say the first is wrong.
The third sentence is also predictive but more hypothetical (less possible and unlikely to happen). The speaker in this sentence is less certain whether the guy may find the right office (I don't think he is likely to find the office). My question here is about the tense reference. Is the speaker referring to the unreal present or to the unreal future? Again, how can I tell?
If it rains tomorrow, be sure to close the windows.
If it should rain tomorrow, be sure to close the windows.
If it is raining tomorrow, be sure to close the windows.
Is the use of "should" above restricted to formal context? Is it likely to occur in everyday conversational conditionals?
It occurs in everday British conversation and, IMO, implies a lower possibility- it's midway between the first and second.
If the truth is known, public opinion will change.
If the truth were known, public opinion would change.
The speaker in the first sentence is somewhat sure that if the truth is revealed, then public opinion will change whereas the speaker in the second sentence sounds less certain (if the truth were to be known-which I don't think would happen, then public opinion would probably change).
My question is again about the tense reference. Do both sentences 1&2 refer to the present unreal or to the future unreal? How can I tell if a predictive or hypothetical statement refers to the real/unreal present or future? Any specific grammatical rules?
The first refers to a possible future. The second seems to me to be looking at an unreal present- the verb 'know' suugests the current situatioon. If it were about the future, it'd be more likely to be something like 'if the truth were to come out'.