Sentence Correction

Can someone explain how can we distinguish between a conditional and a subjunctive mood?

We would start the meeting if Sam were here.
vs
We would start the meeting if Sam was here.

Also, what are the rules that determine the usage of IF/WILL/WOULD/WERE/COULD/IS/WAS etc.?

Below is one such question?

Prior to the battle of Actium, Anthony's generals argued that if Cleopatra goes home many of the Roman senate, Roman people and Roman army would quit their support of Octavianus.

A) goes home many of the Roman senate, Roman people and Roman army would quit their
B) would go home many of the Roman senate, the Roman people and the Roman army would quit their
C) would go home many of the Roman senate, the Roman people and the Roman army will quit their
D) went home, then many of the Roman senate, the Roman people and the Roman army will quit their
E) were to go home many of the Roman senate, the Roman people and the Roman army would quit their

OA E

If we had purchased five shares of Microsoft for $105 at its IPO in 1986, those shares would now be worth over $37,000.

Noticed above sentence at the following tutorial. Instead of "would now be" shouldn't it be "would now have been" ?

https://www.beatthegmat.com/mba/2009/12/ ... -score-760

apex231 wrote:Can someone explain how can we distinguish between a conditional and a subjunctive mood?
Prior to the battle of Actium, Anthony's generals argued that if Cleopatra goes home many of the Roman senate, Roman people and Roman army would quit their support of Octavianus.

A) goes home many of the Roman senate, Roman people and Roman army would quit their
B) would go home many of the Roman senate, the Roman people and the Roman army would quit their
C) would go home many of the Roman senate, the Roman people and the Roman army will quit their
D) went home, then many of the Roman senate, the Roman people and the Roman army will quit their
E) were to go home many of the Roman senate, the Roman people and the Roman army would quit their

OA E

In A, B and C, if Cleopatra GOES home (in A) and if Cleopatra WOULD GO home (in B and C) imply something that might happen in the PRESENT or in the FUTURE. Since the sentence is discussing events in the PAST, eliminate A, B and C.

In D, WILL QUIT (future) cannot be used for a potential action in the PAST. Eliminate D.

The correct answer is E.

For more on IF clauses, check my posts here:

https://www.beatthegmat.com/art-museums-t91368-15.html

https://www.beatthegmat.com/conditional- ... 73666.html