nescio quid faciam, I do not know what to do. (Direct:  quid faciam,
    what shall I do!)

3.  After verbs of expectation and endeavor (exspecto, conor, experior, tempto) we sometimes find an Indirect Question introduced by si; as,—­

    conantur si perrumpere possint, they try whether they can break
    through.

  a.  Sometimes the governing verb is omitted; as,—­

    pergit ad proximam speluncam si forte eo vestigia ferrent, he
    proceeded to the nearest cave (to see) if the tracks led thither.

4.  Indirect Double Questions are introduced in the main by the same particles as direct double questions (Sec. 162, 4); viz.;—­

utrum ... an; -ne ... an; ——­ ... an; ——­ ... ne.

Examples:—­

quaero utrum verum an falsum sit, } quaero verumne an falsum sit, } I ask whether it quaero verum an falsum sit, } is true or false? quaero verum falsumne sit, }

  a. ’Or not’ in the second member of the double question is ordinarily
  expressed by necne, less frequently by an non; as,—­

    di utrum sint necne, quaeritur, it is asked whether there are gods or
    not.

5.  Haud scio an, nescio an, by omission of the first member of the double question, occur with the Subjunctive in the sense:  I am inclined to think, probably, perhaps; as,—­

    haud scio an ita sit, I am inclined to think this is so.

6.  In early Latin and in poetry the Indicative is sometimes used in indirect Questions.

CONDITIONAL SENTENCES.

301.  Conditional Sentences are compound sentences (Sec. 164) consisting of two parts, the Protasis (or condition), usually introduced by si, nisi, or sin, and the Apodosis (or conclusion).  There are the following types of Conditional Sentences:—­

First Type.—­Nothing Implied as to the Reality of the Supposed Case.

302. 1.  Here we regularly have the Indicative in both Protasis and Apodosis.  Any tense may be used; as,—­

    si hoc credis, erras, if you believe this, you are mistaken;

    naturam si sequemur, numquam aberrabimus, if we follow Nature, we
    shall never go astray;

    si hoc dixisti, errasti, if you said this, you were in error.

2.  Sometimes the Protasis takes the Indefinite Second Person Singular (Sec. 356, 3) of the Present or Perfect Subjunctive, with the force of the Indicative; as,—­

    memoria minuitur, nisi eam exerceas, memory is impaired unless you
    exercise it.

3.  Here belong also those conditional sentences in which the Protasis denotes a repeated action (compare Sec. 287, 2; 288, 3); as,—­

    si quis equitum deciderat, pedites circumsistebant, if any one of the
    horsemen fell, the foot-soldiers gathered about him.