Conditions and Suppositions
1. The ‘If, of Open condition (i.e. condition having no implication)
 e.g.: (a) If I make a promise (=whenever I make a promise) I kept it.
 (b) If I made a promise (-whenever I made a promise) I keep it.
 (c) If you will lead, I will follow.
 పై మూడు వాక్యములలోని If clause లలోని షరతులు conditions నెరవేరును అని గాని నెరవేరవు అనిగాని మాట్లాడు నతని సూచన లేదు; కాని ఆ షరతులు నెరవేరిన యెడల principal clause లలోని ఫలితములు విధిగా జరుగును.

‘If I make a prornise’ అను దానికి అర్ధము: “నేను వాగ్దానము చేయుట నిజమనిగాని, నిజముకాదని గానీ మాట్లాడు నతడు సూచించుట లేదు : ఇట్టి వానిని open conditional clauses అందురు.
Note: (1). (a) 6. fl-clause . principal clause కూడ simple present tense వాడబడినది. (b) లో If-clause లోను principal clause లోను కూడ simple past tense వాడబడినది. (C) లో If-clause 5% principal clause 6s వాడబడినది.
simple future tense
ఈ విషయములు పట్టి రూపమున క్రింద చూపబడినవి.
If-clause                                                                                Principal clause
 (a) Simple present                                                                   Simple present
 (b) Simple past                                                                        Simple past
 (c) Simple future                                                                      Simple future
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Note: (2). In each of (a), (b), (c) the verbs in the Principal and Subordinate clauses are both indicative.
A few more examples:
(a) (a) If I ascend up into heaven, thou art there-Bible.
 (b) If you have tears, prepare to shed them now… Shakespeare.
 (c) If the ship leaves the Kakinada port at noon she passes by the Vizag harbour between 3 and 3.30 p.m.
 If he said so, he was wrong.
 If you will be so kind as to help me, I shall be greatly obliged.
 B. The ‘If of Probability (50)
 e.g. If I make a promise, I shall keep it.
పై వాక్యములో If-clause లో simple present tense యును principal clause లో simple future tense యును వాడబడి యున్నవి. ఈ విషయమే పట్టి రూపమున క్రింద చూపబడెను.
If clause
 Simple present
 Principal clause Simple future.
Note :( (2) The verbs in the Principal and Subordinate clauses ae both Subjunctive.
A few more examples:
(a) If the patient wakes up, you will please give him coffee.
 (b) If I meet him to-day, I shall recommend you to him.
 (c) If the ship leaves the Kakinada port at noon she will pass by the Vizag harbour between 3 and 3.30 p.m.
C. The ‘If of Certainty of a future act: e.g. If the ship is to leave the Kakinada port at noon (con- sidered future) she will pass by the Vizag harbour between 3 and 3-30 p.m.
D. The ‘If’ of Chance of a future act: e.g. If the ship should leave the Kakinada port at noon (considered future) she will pass by the Vizag harbour between 3 and 3-30 p.m.
E. The ‘If of Ignorance (on the part of the speaker) of the condition being a fact or not. e.g. If the ship is leaving now the Kakinada port, she will pass by the Vizag harbour between 3 and 3-30 p.m. N. B. For further information see ‘Conditional Tense’ on pages 119-121.