УСЛОВНЫЕ ПРЕДЛОЖЕНИЯ

     Условные придаточные содержат указание на условие, от которого зависит осуществление того, о чем говорится в главной части. Присоединяются к главной части посредством союза if. Вместо if могут использоваться другие союзные средства:

                            providing (provided)            - при условии, что
                            in case                                  - в случае, если
                            suppose (supposing)          - предположим, что
                            but for                                    - если бы не

Условные предложения бывают трех типов.

I. Реальное условие

     Предложения, выражающие реальное условие, относятся к будущему времени и могут выражаться тремя способами.

1. If he comes, I will tell him about it.
Если он придет, я ему скажу об этом.
2. If he should come, I will tell him about it. (меньшая вероятность)
3. If he come, I will tell him about it. (употребляется в письменной речи)

II. Малореальное условие

     Предложения, выражающие малореальное условие, относятся к настоящему и будущему времени. В переводе появляется частица бы.

If I saw him tomorrow, I would tell him about it.
Если бы я увидел его завтра, я бы сказал ему об этом. (Подразумевается, что это маловероятно).

If he were here, he would help us.
Если бы он был здесь, он бы нам помог.

If I were you, I would do it immediately.
Если бы я был на вашем месте, я бы сделал это немедленно.

III. Нереальное условие

     Предложения, выражающие нереальное условие, относятся к прошедшему времени.

If I had seen him at the conference yesterday, I would have told him about it.
Если бы я увидел его вчера на конференции, я бы сказал ему об этом.

But for him, I would not have finished my experiment.
Если бы не он, я бы не закончил свой эксперимент.

IV. Смешанные случаи

     Одним из смешанных случаев является выражение формальной просьбы.

I would be grateful to you if you would send me your paper.
Я был бы вам очень благодарен, если бы вы прислали мне свою статью.

V. Бессоюзное соединение

     Иногда придаточное условия вводится без союза. Тогда на первое место выносится глагол. Переводится также условным предложением.

Should he come, I will tell him about it.
Если он придет, я ему скажу об этом.

Had I seen him, I would have told him about it.
Если бы я его увидел, я бы ему сказал об этом.

Упражнения

I

1. If we examine a large number of such pulses, their amplitudes will not all be the same.
2. Should lightning-impulse stress occur, layer windings will ensure an optimal voltage distribution with few oscillations.
3. Should the cover be removed, its interlock contacts will cause the power converter to be switched off.
4. If water is substituted for the air, its absorption properties per unit mass do not differ greatly because the average atomic number of water is much the same as that of air.
5. If the interaction does not occur within the detector, these uncharged radiations (e.g., neutron or gamma rays) can pass completely through the detector volume without revealing the slightest hint that they were ever there.
6. For example, if an energy calibration is to be carried out for electron detectors, it is much more convenient to use a source of monoenergetic electrons.
7. In absence of the external force, this work corresponds to the energy loss (or gain) of the charges, provided that the velocity of the charge does not change significantly.
8. It can be shown that the range of a charged particle in a compound material can also be estimated provided its range is known in all the constituent elements.
9. We find that, of the models considered, only that proposed by Bando et al. is able to consistently account for all information, provided one allows its parameter A to vary from the usual value of 2 to 2.4.
10. If the ice did not flow off Antarctica, all the water in the oceans would be deposited there.
11. If neutrinos (or antineutrinos) were present after the decay to cancel the additive separate lepton numbers of the electron and muon, the decay would not violate anything.
12. If all the default conditions were satisfactory for the problem, only the mnemonic SDFF would be required.
13. W and D would be diagonal if there were no isospin-violating effects.
14. If such analyses were used in dynamic translation, high performance degradation would be experienced during the translation.
15. Calibration would be extraordinary difficult were it not that Nature herself supplies the means through the phenomenon known as aberration of starlight.
16. If the full Lagrangian statistics of the flow were known, then the particle dispersion could be calculated.
17. If the sum of these three angles were known, the mass of the lepton could be reconstructed.
18. Were the same wire to be annealed at 700 - 800°C for a few hours, the J may drop by an order of magnitude, leaving T and B basically unchanged.
19. Note that the second term for Y plane equals XZ plane/2 and represents the displacement that would have occurred had the deflection Z plane all occurred at the single point x/2.
20. Had those first authors given their results more thought, they too might reverse their conclusion.

II

1. If these variables were unrelated the probability would be 0.01.
2. If such aberrant coding were due to the differential modification of tRNAs, this modification would be expected to be most noticeable in these tRNAs.
3. If this simplification were the only reason for the deviation, however, the difference of these binding constants would be surprisingly large.
4. If this were the case for the dicarboxylic amino acids, one would expect that RNAse hydrolysis of the aminoacyl-tRNAs would produce two isomeric amino-acyladenosines for each of these aminoacids.
5. Even this low level would not be required in the cytoplasm if the oligonucleotide could gain access to the nucleus.
6. Thus, the observation that mutation or chemical modification of residues at many different locations within the polymerase cleft has an effect on DNA binding is as expected; indeed, it would be surprising if this were not so.
7. Extension from a misaligned DNA molecule could occur if the template were to "collapse" around the lesion site, placing the primer terminus opposite the template base to the 5'- side of the lesion.
8. Evidently, tRNAs with certain combinations of mutations could be isolated only if they exhibited a very low tRNA level, or could be maintained only under conditions of reduced efficiency.
9. If KBL were of similar magnitude as K_AL, a plot of 1/Kp against [L] would not be linear, but would show a deviation resulting from the quadratic term in Eq.(7).
10. The complex activity profiles shown by lipoxygenase in reverse micelles would be easier to interpret if the changes in the phase where the enzyme is active could be followed.
11. If free hydroxyl radicals were generated in solution by the S,10-phenanthroline-copper system, DNA cleavage would be observed as is the case for ferrous-EDTA.
12. The existence of the z-DNA structure, first observed at high salt or alcohol concentrations, would be of little interest to the molecular biologist, but for two observations.

III

1. If this is the case, the value of the quotient will be determined by continuity.
2. Provided that the integral can be differentiated under the sign of integration we find the following.
3. Lagrange problems are said to be autonomous provided the functions ƒ   are independent of time.
4. If such a neighbourhood were free from points of , n (, z) would be defined and constant in the neighbourhood.
5. Thus, any coefficient would be topologically allowed if T and l were chosen appropriately.
6. Were x=0 conjugate to x= there would exist a nonnull solution such that (0) = ()=0.
7. Obviously, greater coherence would be achieved if we defined normal families of meromorphic functions with the help of uniform convergence on the Riemann sphere.
8. This graph is acyclic, for if there were a cycle, all nodes on the cycle would be in the same strongly connected component.
9. Had we used the stronger stop criterion 2 (non-strict instantiation), the partial evaluator would have produced the same code as in figure 3.
10. Conclusion: everything can be represented linearly provided one takes a sufficient number of dimensions.