Conditional sentences

Question 1

Factual conditional

Answer 1

si/nisi + indicative verb, + indicative main verb
can also be followed by a question or command.

often seen with a future perfect-
If you pay attention, you will be able to answer the question.
si attenderis, respondere poteris.

Question 2

Hypothetical conditional

Answer 2

si/nisi + subjunctive, + subjunctive main verb
often in the same tense

PAST-   pluperfect subjunctive
 If you had kept quiet, you would have appeared clever.
 si tacuisses, sapiens uisus esses.
PRESENT-   imperfect subjunctive
 If she were rich, she would not be lacking a husband.
 si diues esset, marito non careret.
FUTURE-   present subjunctive
 If we were to do business, my wife would never speak to me again.
 If we did business,
 si negotium agamus, uxor mihi numquam iterum loquatur.

Question 3

Past hypothetical conditional

Answer 3

if the main verb is a verb of obligation or possibility (debeo, possum, esse +gerund) then it will be an (past or imperfect) indicative.