Supplimentary grammar notes on subjunctive mood:

SEQUENCE OF TENSES
Verbs show absolute/real time only when they're in indicative mood; in every other mood, verb show only time relative to the verb in the indicative mood.
The sequence of tenses are rules that apply only to subjunctive verbs in subordinate clauses.

PRIMARY TENSES (present and future) : Present, Future, Perfect (as present perfect, e.g. "I have come"), Future perfect,

- the main verb in primary tense - the subordinate verb in the subjunctive present for ongoing action.
Edunt ut vivant. (They eat so that they may live.)
Haec dicit ut pericula comprehendamus. (He is saying these things, so that we may understand the dangers.)
Via ita longa est ut ad urbem numquam veniant. (The road is so long that they never come to the city.)

- the main verb in primary tense - the subordinate verb in the subjunctive perfect for completed action.
Cognoscam quid feceris. (I will find out what you did.)

SECONDARY TENSES (historical): Imperfect, Pluperfect Perfect (as simple past, e.g. "I came")

- the main verb in secondary tense - the subordinate verb in the subjunctive imperfect for ongoing action.
Edebant ut viverent. (They ate so that they might live.)

- the main verb in secondary tense - the subordinate verb in the subjunctive pluperfect for completed action.
Cognovi quid fecisses. (I found out what you had done.)
Haec dicebat ut pericula comprehenderemus. (He was saying these things, so that we might have understood the dangers.)
Via ita longa erat ut ad urbem numquam venirent. (The road was so long that they had never come to the city.)

1) PURPOSE CLAUSES
There is only one way to show purpose: a full subordinate clause introduced by "ut" or "ne" (the negative) plus a finite verb in the subjunctive mood. It never uses the infinitive to show purpose, the way English does.

Id facit ut eos adiuvet. (He is doing it to help them [or in order to help them, or so that he may help them.)
Veniunt ne civitates deleantur. (They are coming so that the cities will not be destroyed.)
Haec dicit ut discipuli omnia intellegant. (He is saying these things so that the students will understand everything.)
Multos libros legit ne stulta videatur. (She reads many books so that she won't seem foolish.)

English has basically two way to show purpose:
(1) infinitive, sometimes supplemented with "in order,"
"She is coming to help (or in order to help)".
"They are sending him to tell you what to do".
"The dog has a long nose to smell better".
"In order to serve you better, our store has installed anti- theft devices".

(2) a subordinate clause introduce by "so that" or "so" or "in order that" often with the conditional mood of the verb. "She is coming so that she may help".
"They are sending him so that he may tell you what to do".
"The dog has a long nose so that it may smell better".
"In order that we may serve you better, our store has installed anti-theft devices".


2) RESULT CLAUSES
Result clauses are frequently anticipated by adverbs or special adjectives in the main clause -- "ita, sic, tam, tantus, -a, -um". The clause itself it introduced by "ut" when the result clause is positive, and by "ut" with a negative in the clause when the result is negated. The verb is put into the subjunctive mood.

Id sic fecerunt ut omnes metu liberarentur. (They did it in such a way that everyone was freed from fear.)
Scripserunt ita male ut nemo litteras legere posset. (They wrote so badly, that no one was able to read the letter.)
Tantum ferrum tenebat ut territi hostes fugerent. (He was holding such a great sword that the terrified enemy ran away.)

In English a Result Clause often comes with adverbs like "so" or "such" in the main clause, and the result clause itself is introduced by the subordinating conjunction "that".

"The eclipse made the sky so dark that it seemed like night".
"They wrote so badly that no one could read the letter".
"She was such a good athlete that she easily jumped over the fence".


3) CONDITIONAL STATEMENTS
A conditional sentence has two parts: the "if" clause - the "protasis", and the "then" clause - the "apodosis".
The protasis states the condition under which the main clause will be (will not be), is being (is not being), or was (was not), fulfilled:

A. OPEN / SIMPLE CONDITIONS
(one that does not imply any doubt about the fulfillment of the condition stated in the protasis)

i) PRESENT OPEN
“if” - ind. present, “then” - ind. present
Si hoc facit, beatus sum.(If he is doing this, then I am happy.)

ii) FUTURE REAL
“if” - ind. future, “then” - ind. future
Si hoc faciet, beatus ero. (If he does this, then I will be happy.)
- Note that in the Latin future real, both the protasis and apodosis are future, whereas the English protasis is present.

iii) PAST OPEN
“if” - ind. past, “then” - ind. past
Si hoc fecit, beatus eram. (If he did this, I was happy.)


B. UNREAL CONDITIONS

i) FUTURE LESS VIVID
“if” - subj. present, “then” - subj. present
Si hoc faciat, beatus sim. (If he should do this [I doubt he will], I would be happy.)

ii) PRES. CONTRARY TO FACT
“if” - subj. imperf., “then” - subj. imperf.
Si hoc faceret, beatus essem. (If he were doing this [but he is not], I would be happy [but I'm not].")

iii) PAST CONTRARY TO FACT
“if” - subj. plpf., “then” - subj. plpf.
Si hoc fecisset, beatus fuissem. (If he had done this [but he did not, I would have been happy [but I wasn't].)

The basic formulae for English conditional sentences.

A. Simple or Open Conditions

i) PRESENT SIMPLE
“if” - pres. indic., “then” - pres. indic.
If x approaches 0, then the value of f(x) approaches infinity.

ii) FUTURE MORE VIVID
“if” - pres. indic., “then” - fut. indic.
If you saw him yesterday, then he was here."
(Again, the speaker is not saying that it is unlikely that you will come tomorrow, but if you do, then... When a simple or open condition applies to a future event, it is often called the "future-more-vivid," or the "future real" condition.)

iii) PAST SIMPLE
“if” - past. indic., “then” - past indic.
If you come tomorrow, I will be happy."
(The speaker is not doubting or suggesting that you did not see him yesterday, but if you did, then he was here.)

B. Unreal (and Contrary to Fact) Conditions
(The speaker may be implying or explicitly stating that the condition stated in the protasis will not be, is not, or was not fulfilled.)

i) FUTURE LESS VIVID
“if” - should; were to, “then” - would
"If you should come (or were to come) tomorrow, then I would be happy."
(The speaker doubts that you will come, but if you should, then he would be happy.)

ii) PRESENT CONTRARY TO FACT
“if” - imperf. indic., “then” - would
"If you were eight and a half feet tall, you would be a great basketball player."
(But you are not eight feet tall, so you are not a great basketball player. But if you were...)

iii) PAST CONTRARY TO FACT
“if” - plperf. indic., “then” - would have
"If George had been there, we would have won the game."
(But he was not there, so we did not win the game. But if he had been there...)

4) CUM AS A SUBORDINATING CONJUNCTION
In some respect, "cum" is is similar to the English conjunction "as", which has quite a range of meanings, and at times seems to be using many of them all at once.

There are two categories of meanings for "cum":

i) strictly temporal (when);
When "cum" is temporal, the mood of the verb in its clause is often indicative. It is almost always indicative when the tense of the verb in the main clause is present or future tense. When the tense of the main verb is one of the past tenses, then the mood of the "cum" clause is most often subjunctive.
Cum responderit [fut. perf.], omnia intellegetis. (When he answers (will have answered), you will understand everything.)

ii) circumstantial (as, whereas, since, because, although). It sets a backdrop for the the action in the main clause without spelling out what the relationship is between them. A circumstantial "cum" clause can be translated as "since", "because", and "although" (causal and concessive).
When the "cum" clause is circumstantial, the mood of its verb is always subjunctive and observes the sequence of tenses.

contemporaneous time - subjunctive imperfect
Cum responderet, non aderatis.(When he was answering, you were not present.)

time prior - subjunctive perfect
Cum responderit, omnia iam intellegitis.(Because he answered, you now understand everything.)

time prior - subjunctive plusperfect
Cum respondisset, omnia intellexistis.(Because he had answered, you understood everything, or "When he had answered..". or "Since he had answered”..)

concessive - subjunctive plusperfect
Cum respondisset, non tamen intellexistis.(Although he answered, you nevertheless did not understand.)


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