1. Lesson 5 (Oct. 13) Comparisons Comparing dimensions, properties and quantities.

2. Comparatives Sentences that compare two things: …… comparative (adjective -er ) ‘than’ ………. – x is longer than y. – y is shorter than x. – The Intel Pentium 4 is faster than the Intel 80486. Another comparative form: ……… more __________ than …… ……… less ___________ than …… – Hydrochloric acid is more dangerous than citric acid. – Citric acid is less dangerous than hydrochloric acid. – Sea water contains more salt than fresh water.

3. Comparatives – more examples …… comparative (adjective -er ) ‘than’ ………. 1.A meter is longer than a yard. 2.The Indian Ocean is deeper than the South China Sea. 3.In summer Taipei is hotter than Puli. 4.The streets of Puli are narrower than the streets of Taipei. 5.Taipei is a busier city than Kaohsiung. 6.Microwaves are shorter in wavelength than radio waves. 7.The transistor was invented later than the vacuum tube. User the –er form for short adjectives:  longer – longer  short – shorter  narrow – narrower  deep – deeper  tall – taller  big – bigger  fat – fatter  hot – hotter  busy – busier  late – later

4. Comparatives Look up a dictionary for the comparative form:

5. Comparatives

6. Modifiers in Comparison Statements As in all English sentences, comparison statements can contain modifiers to give more information or more precise meaning. Other examples: 1.Gold is heavier in atomic weight than iron. 2.The Fourier transform is easier to understand than wavelet transform. 3.Men are taller on average than women. Microwaves are shorter in wavelength than radio waves. Without the modifier, the statement is grammatically correct but not very meaningful.

7. Another Comparative Form: more/less ___ than Examples: – Hydrochloric acid is more dangerous than citric acid. – Citric acid is less dangerous than hydrochloric acid. This form is used for most adjectives. In technical writing, this form is preferred. (except short adjectives) YES: – The Van der Pol oscillator is more stable than an LC circuit. NO: – The Van der Pol oscillator is stabler than an LC circuit.

8. Adjectives without –er comparative form Whether to use –er form is actually complicated. Look up a dictionary and read more books/papers! no –er form given

9. Another Comparative Form: more/less ___ than Never use the –er and “more than” forms together: No, no, no! – The MOSFET is more commoner in both digital and analog circuits than the bipolar junction transistor. Yes: – The MOSFET is more common in both digital and analog circuits than the bipolar junction transistor.

10. The have ________ than Structure What we saw was the structure: be ___________ than – Car A is cheaper than car B. – Car B i s more expensive than car A. – Car A is less expensive than car B. The same statement can be written in another structure: have ___________ than – Car A has a lower price than car B. – Car B has a higher price than car A. nouns

11. The have ________ than Structure Examples: 1.The Indian Ocean is deeper than the South China Sea. The Indian Ocean has a greater depth than the South China Sea. 2.In summer Taipei is hotter than Puli. In summer Taipei has higher temperatures than Puli. 3.The streets of Puli are narrower than the streets of Taipei. The streets of Puli have smaller widths than the streets of Taipei. 4.Microwaves are shorter in wavelength than radio waves. Microwaves have shorter wavelengths than radio waves. 5.The transistor was invented later than the vacuum tube. The transistor has a shorter history than the vacuum tube.

12. The have ________ than Structure This structure is an extension of structure 2 for describing dimensions and properties: 1.The Indian Ocean has an average depth of 3,890 m. The Indian Ocean has a greater depth than the South China Sea. 2.Water has a boiling point of 100  C. Water has a higher boiling point than alcohol. 3.Microwaves have wavelengths of 30 cm to 3 mm. Microwaves have shorter wavelengths than radio waves. 4.The transistor has a history of about 90 years. The transistor has a shorter history than the vacuum tube.

13. Comparing Quantities with have ________ than Countable quantities: – Building A has more rooms than Building B. – Building B has fewer rooms than Building A. – A hexagon has more sides than a triangle. – A triangle has fewer sides than a hexagon. Uncountable or singular quantities: – Car A consumes more petrol than Car B. – Car B consumes less petrol than Car A. – Sea water contains more salt than fresh water. – Fresh water contains less salt than sea water.

14. Superlatives When comparing with more than one things, the superlative form is used: … the _____- est …superlative of… ____ -er than … … the most ______ … superlative of … more _____ than … … the least ______ …superlative of… less/fewer ____ than … 1.The Indian Ocean is deeper than the Pacific and the Atlantic.  The Indian Ocean is the deepest ocean in the world. 2.Taipei is a busier city than all other cities in Taiwan.  Taipei is the busiest city in Taiwan. 3.The electronics group has more students than the communications and systems groups.  The electronics group has the most students. 4.Hydrogen is the lightest gas. 5.Hydrogen has the least atomic weight.

15. …not as ________ as... Instead of the more … than comparative form, one can also use the following equivalent form, but be careful when comparing nouns: Gold is heavier than iron. = Iron is not as heavy as gold. The Indian Ocean is deeper than the Pacific Ocean. = The Pacific Ocean is not as deep as the Indian Ocean. Taipei is a busier city than Kaohsiung. = Kaohsiung is not as busy a city as Taipei. Building A has more rooms than Building B. = Building B does not have as many rooms as Building A. Car B consumes less petrol than Car A. = Car B does not consume as much petrol as Car A. Water has a higher boiling point than alcohol. = Alcohol does not have as high a boiling point as water.