CONDITIONAL SENTENCES.

Here you have some examples of conditionals and some exercises to practice.

a) type-1. (Real)1. [If most of the heat pumps are in the cooling mode], the temperature

of theloop water rises.

2. [If the current is limited to some safe value], the voltage across the diode is

constant, independent of the current through the diode.

3. [If light is allowed to fall on the junction of a reverse-biased PN diode], the

current will be proportional to the amount of light.

4. [If the ends of the revolving coil are connected to a pair of contact rings, on

each of which presses a brush], the machine will deliver alternate currents.

5. [If studs are used], take care not to damage them.

6. [If this looks too simple], let us develop a more complex procedure.

7. [If we trace out the instructions of an algorithm], then for all cases the

algorithm will terminate after a finite number of sets.

8. Conversely, [if service conditions alter a material’s structure], the engineer

must anticipate that changes will occur in properties and performance.

9. [If this precaution is not taken], the n+-type contact region may touch the ptype

base and result in a low collector-base breakdown voltage.

10 [If the compression in the diffuser is carried to a high enough pressure], an

efficient engine can be obtained without a compressor.

11. [If only few specimens are to be tested], the empty places in the freezer

should be filled with dummies, [unless it has been shown that the correct temperature cycle is achieved without this precaution].

12 [If specified]1, the zinc coating is in accordance with ISO standard.

13. The principle of transmissibility states that the conditions of equilibrium or motion of a rigid body will remain unchanged if a force F acting at a given point of the rigid body is replaced by a force F’ of the same magnitude and the same direction, but acting at a different point, [provided that the two forces have the same line of action].

14. It will retain these properties indefinitely, [provided there is no change in the internal structure of the material].

15. It may not always be necessary to understand the precise definition itself, [provided one can understand the significance of the term or figure in relation to the diagram, chart or calculation involved].

16. [Unless excited by external means]2, the one electron of a hydrogen atom will occupy the lowest orbital.

17. [In the event of an LNG tanker running aground or becoming stranded in some other way], that type of operation is necessary.

18. It is important to remember that a variable stands for the same object [wherever it occurs in a rule].

19. [If in doubt] add a bit more, and don’t use additives [unless you are confident of what they can do and are sure that only the right amount will be used].

20. [If a cylinder head is too tight], do not drive a chisel or screwdriver between the cylinder block and head to remove it.

1 Note the omission of the pronoun and the verb to be in if it is specified = if specified.2 : unless it is excited = unless excited.

b) type-2 (hypothetical)

1. [If the base collector junction were3 fabricated like the pn junction in a

conventional diode], only a tiny reverse current would flow.

2. [If the bar in tension were absolutely rigid], it would increase in length

slightly.

3. [If a thermometer were inserted into each block and the blocks were placed

in direct sunlight], the temperature of the black block would rise at a much faster ratethan that of the silver one.

4. Copper and aluminium are both fairly weak, [but if they were mixed together],

the result would be an alloy called aluminium bronze, which is much stronger thaneither pure copper or pure aluminium.

5. In fact, it would actually cause the truck to move downward [if it were not for

the presence of the ground].

6. [Were it not for the improvements made in steel production]4, the railroad

system could not have developed.

3 In type-2, were is used instead of was in the if-clause. If I were you, ...4 Note the ‘subject + verb’ inversion to mark the elision of the conditional subordinator (If). This can occurin type-2 (only if the verbs were or should are used in the if-clause), and in type-3

c) type-3 (Impossible)

1. [If the bearings had shown fine scratches], they would have been re-used.

2. [If scientists had not invented the atom bomb], disasters such as Hiroshima

would not have occurred.

3. This computing time is a little disturbing since we know that [in case the

matrices had been represented as two dimensional arrays], we could have obtainedthe transpose of an n*m matrix in time O(nm).

4. [Had the heating unit been located near the ceiling], the warm air would have

remained there, and very little convection current would have been generated todistribute the energy.

PRACTICE

1. Write the verbs in the appropriate tense.

1. If the current ___________ (be limited) to some safe value, the voltage acrossthe diode is constant, independent of the current through the diode.

2. If you ___________ (use) a hard-to-guess password that contains a mix ofnumbers and letters, hackers would find your system more difficult to crack.

3. If it ___________ (be) not for the improvements made in steel production, therailroad system could not have developed.

4. If Stephenson ______________ (invent) the steam locomotive, some otherengineer would have invented something similar.

5. In case the adequate measures had been taken, the accident ____________ (canbe avoided).

6. If heat loss in power stations _________ (can be used) more efficiently,cogeneration power plants would play an even bigger role in energy production.

7. A BS in physics provides an ideal preparation for most engineering mastersprograms, provided that the BS curriculum __________ (be supplemented) by fouradditional courses.

8. Customers would be pleasantly surprised if automobile manufacturers__________ (try) to solve driving problems with a change in car design.

9. In the event of a tanker ___________ (sink) near the coast, measures should betaken to prevent oil from reaching the coast.

2. Rewrite the conditional sentences using inversion.

1. If engineers had planned on tunneling the highway through most of its route,maybe public opposition to the project would not have been as fierce.

2. If it were not so potentially dangerous, nuclear energy would not be so polemic.

3. If vaccines had not been invented, many people would still die from commonillnesses.

4. If the Hindenburg airship had used helium instead of hydrogen, it wouldn’thave exploded in New Jersey.

5. If you should require minimum weight with high tensile resiliency, carbon fibrewould be the right material for you.