1. Conditional Sentences if then

2. Agenda Definition Types and Uses –Case1: First Conditional—probable –Case2: Second Conditional—impossible –Case3: Third Conditional—no longer possible Exercise References

3. Definition Conditional sentences contain two sections –The main clause gives the result of the condition. –The conditional clause explains the condition. Conditional clauses usually begin with if, unless, provided that, or a similar conjunction. If the smoke gets too bad, we will have to stop soldering. We cannot continue this experiment unless we wear protective masks. Conditional clause result Conditional clause

4. If the smoke gets too bad, we will have to stop soldering. Clauses Conditional clauses can be at the beginning of a sentence or at the end of a sentence. We will have to stop soldering if the smoke gets too bad. Conditional clause result Conditional clauseresult

5. First Conditional— PROBABLE The condition refers either to present or to future time. Hence, it can become true. The sequence of tenses is: –Main clause (result): future tense –Conditional clause (condition): simple present tense If we finish the design today, we will be able to start development tomorrow. Main clause = result = future tense Conditional clause = condition = simple present tense Let’s do it!

6. Second Conditional— IMPOSSIBLE The condition will not be met and is impossible. It is stated in the simple past tense. The sequence of tenses is: –Main clause (result): would + verb –Conditional clause (condition): simple past tense If we finished the design today, we would be able to start development tomorrow. Main clause = result = would + verb Conditional clause = condition = simple past tense Argh! We can’t do it!

7. Second Conditional—WERE Usage of “were” for a singular noun is a special case Use “were” in the conditional clause only for an impossible statement The sequence of tenses is: –Conditional clause: If + were –Main clause: would + verb If I were rich, I would buy a Porsche. – not likely When I was rich, I bought a Porsche. – this did happen! If platinum were not so expensive, more circuits would be constructed with it.

8. Third Conditional— TOO LATE The condition can not be met any more because it is too late. It is stated in the past perfect tense. The sequence of tenses is: –Main clause (result): would + have + past participle of the verb –Conditional clause (condition): past perfect tense If we had finished the design today, we would have been able to start development tomorrow. Main clause = result = would + have + past participle of verb Conditional clause = condition = past perfect tense But it’s too late now.

9. Passive Voice Using Passive Voice in If-Clauses can make the tense-sequence grammar very difficult! Soldering will have to be stopped if the smoke cannot be controlled. Present passive voice Future passive voice Soldering would have to be stopped if the smoke could not be controlled. Past passive voice Would + passive voice Soldering would have had to be stopped if the smoke could not have been controlled. Past perfect passive voice Would + past perfect passive voice

10. Exercise If the phased locked loop ______ (not find) to be a useful element in may types of communication systems, this technology _______(not gain) so much popularity. If it ________ (apply) correctly, it ____ (become) useful in two fundamentally different ways: 1. It can serve as a demodulator, if it ____ (use) to follow phase or frequency modulation and 2. it can serve to track a carrier or synchronizing signal which may vary in frequency with time. If it ______ (operate) as a demodulator, we _____ potentially______ (can use) the phase locked loop as a matched filter operating as a coherent detector. If it______ (use) to track a carrier, we _________ (can employ) it as a narrow-band filter for removing noise from a signal. If, in the old days, Newton _________ (make) such a discovery, today’s engineering world _______ (see) a much wider use of this technology. (adjusted from Mills, Thomas B. (1971). The Phased Lock Loop IC as a Communication System Building Block. National Semiconductor Application Note 46. Available http://www.national.com/an/AN/AN- 46.pdf.)http://www.national.com/an/AN/AN- 46.pdf

11. Answers If the phased locked loop had not been found (not find) to be a useful element in may types of communication systems, this technology would not have gained (not gain) so much popularity. If it is applied (apply) correctly, it will become (become) useful in two fundamentally different ways: 1. It can serve as a demodulator if it is used (use) to follow phase or frequency modulation and 2. it can serve to track a carrier or synchronizing signal which may vary in frequency with time. If it were operated (operate) as a demodulator, we could potentially use (can use) the phase locked loop as a matched filter operating as a coherent detector. If it were used (use) to track a carrier, we could employ (employ) it as a narrow-band filter for removing noise from a signal. If, in the old days, Newton had made (make) such a discovery, today’s engineering world would see (see) a much wider use of this technology.

12. More Information http://ccc.commnet.edu/sensen/part4/esltips/esl_c onditional.html http://ccc.commnet.edu/sensen/part4/esltips/esl_c onditional.html http://www.ccc.commnet.edu/grammar/conditional 2.htm http://www.ccc.commnet.edu/grammar/conditional 2.htm http://web2.uvcs.uvic.ca/elc/studyzone/410/gramm ar/2cond.htm http://web2.uvcs.uvic.ca/elc/studyzone/410/gramm ar/2cond.htm http://www.bartleby.com/64/pages/page266.html

13. Conditional Sentences: Quiz Please take the Conditional Sentences Quiz on WebCT now.