Summary

A group of scientists at Rensselaer Polytechnic Institute have developed a new solar energy technology which is more efficient and can greatly reduce the carbon dioxide emissions.
Conventionally, scientists use semiconductor materials like silicon to produce solar cells and photovoltatic panels. Portion of the light incident on the semiconductor materials is absorbed to activate the electrons. Electric field(s) within the photovoltalic cells forces the electrons flow in certain direction to generate current. However, the process is too costly to make it a feasible alternative to the electricity form the power grid. The major breakthrough of the new technology is to minimize the solar cell to a postage stamp size and improve the efficiency from the conventional 14% to nearly 80%. The systems consist of lenses that can automatically trace the movement of the sun all the time and let the sunlight incident perpendicularly onto the solar cells. The lenses are incorporated into glass buildings and window panes to provide nearly 50% of the energy needed of the building operation.
In US today, residential and commercial buildings use 2/3 of all electricity and produce 35% of all carbon dioxide emissions, which is a great proportion. Both Anna Dyson, an architectural scientist, and Michael Jensen, a mechanical engineer, confirmed that the new technology is critical to reduce our dependency of fossil fuels and global warming.
The full-size prototype will be installed into the building at the Center for Excellence and Environmental Energy Systems and the Fashion Institute of Technology in 2008 and 2009 respectively.

(252 words)
The original passage “Mechanical Engineers Create High-tech Solar Panels” is from http://www.sciencedaily.com/videos/2007/0507-bringing_sunlight_inside.htm

Exercises on prepositions

1 He made his escape by jumping ______ a window and jumping ______ a waiting car.

A. over/into

B. between/into

C. along/up

D. by/on

E: up to/ out of

2 To get to the Marketing department, you have to go ______ those stairs and then ______ the corridor to the end.

A. over / into

B. between / into

C: out of / between

D: out of / into

E: up / along

3 I saw something about it ______ television.

A: in

B: on

C: at

D: through

E: with

4 I couldn't get in ______ the door so I had to climb ______ a window.

A: through / in

B: between / into

C: out of / between

D: out of / into

E: up / along

5 She took the key ______ her pocket and put it ________ the lock.

A: over / into

B: between / into

C: out of / in

D: by / on

E: up to / out of

6 He drove ______ me without stopping and drove off ______ the centre of town.

A: from / into

B: towards / over

C: along / up

D; past / towards

E: in / next to

7 I took the old card ______ the computer and put ______ the new one.

A: through / in

B: out of / in

C: out of / between

D: out of / into

E: up / along

8 I went ______ him and asked him the best way to get ______ town.

A: from / into

B: towards / over

C: along / up

D: by / on

E: up to / out of

9 It's unlucky to walk ______ a ladder in my culture. I always walk ______ them.

A: through / in

B: out of / in

C: under / around

D: out of / into

E: up / along

10 The restaurant is ______ the High Street, ______ the cinema.

A: through / in

B: out of / in

C: under / around

D: in / next to

E: up / along

11 Sally left school ______ the age of 16 and went to work ______ a bank.

A: through / in

B: out of / in

C: under / around

D: in / next to

E: at / in

12 He jumped ______ the wall and ______ the garden.

A: over / into

B: towards / over

C: along / up

D: by / on

E: up to / out of

13 He was driving ______ 180 miles per hour when he crashed ______ the central barrier.

A: at / into

B: out of / in

C: under / around

D: in / next to

E: at / in

14 She ran ______ the corridor and ______ the stairs to the second floor.

A: from / into

B: towards / over

C: along / up

D: by / on

E: in / next to

15 John is the person standing ______ the window, ______ the woman with the long blonde hair.

A: at / into

B: beside / next to

C: under / around

D: in / next to

E: at / in

16 When the bull ran ______ me, I jumped ______ the fence.

A: from / into

B: towards / over

C: besides /next to

D: by / on

E: in / next to

17 Look, that car's ______ fire.

A: through

B: with

C: in

D: into

E: on

Answers will be in the comment. Have a try first~

Reference: http://www.better-english.com/grammar/prepositions.htm

Hu Xuan’s pitfall

One of my common grammar mistakes is prepositions. My problem is to decide which one to use and which one not to use. There are only a few prepositions words in English. However, they are used extremely frequently, expressing various meanings in the context. So far, I have already used three prepositions in this blog entry. Here comes the 4th. The meanings of sentences vary a lot with different choices of prepositions.

Example: Were there any calls for me?
You had a call from Fred.
I made a call to a friend in London.

In what way, prepositions are used?

Prepositions are usually used before none, pronouns or gerunds. They show the relationship between a noun or pronoun and another word or words.

Example: The girl on the bike looked at the children on the swing.

The most commonly used prepositions are about, above, among, at, in, on, before, behind, between, during, for, from, into, over, towards, until, upon, within, without.

More often, prepositions are used with other words.
#With verbs:
e.g. aim at; allow for; appeal to; believe in; blame for; coincide with; comment on; refrain from; insist on
#With adjectives and participles:
e.g. Accompanied by; accustomed to; characterized by; common to; comparable with; equal to; essential for; inferior to; worthy of; regardless of; indifferent to…
#With nouns and phrases
e.g. in accordance with; a capacity for; to a high degree; the opposite of; for the purpose of; with reference to

How to improve?
Basically, there is no short cut to improve the accurate usage of prepositions. The best way is to familiarize ourselves with the words in phases. Given the context, we can understand better. To read more also helps us to differ the various usages of the prepositions.

Here is a short essay I extracted from http://www.english-test.net/lessons/48/index.html for your leisure reading.

Our learner was in a terrible state. He knew he wanted to go somewhere but he didn't know how. At this moment he was standing near a bridge. Should he go by bus, by train, by car, by boat or possibly quite simply on foot? He could walk across the bridge, under the bridge but he couldn't possibly jump over the bridge. He just knew he wanted to get out of town. Once he had arrived there by car he could obviously get out of the car or the train or the bus but he'd have to get off the boat. And now he had arrived in the town centre and was sitting inside the tourist office looking out of the window. Well, he couldn't actually see through the window because the glass was very dirty. He left the tourist office and stood outside for a few minutes thinking what to do next. He saw a policeman coming towards him and he thought he'd ask him where to go.But the policeman walked past him and went along the street taking no notice of him. Anyhow when he thought about it, what could a police officer do for him? The trouble was that he didn't speak the language although he had learnt a few phrases by heart. He knew how to say: On what day is there a festival? At what time do the shops shut? Can I put my bike against the wall? None of these questions would be of use to him. What he really wanted to know was: Where is there a hotel? He was on the point of giving up when he saw a wonderful hotel in front of him. He walked up to the reception and within minutes he was sitting in a beautiful bedroom that looked over the sea. He had a fabulous meal in the restaurant and then went back to his room. He got into bed and fell into a deep sleep. It was in the middle of the night that he suddenly realized he wouldn't have enough money to pay for the accommodation. He decided to continue with his sleep and when he woke up he got ready and went down to the restaurant for his breakfast. He didn't leave that hotel for three weeks. That was how long it took for him to pay for that overnight stay by working in the kitchen as a washer up.

References: http://clc.cqu.edu.au/FCWViewer/getFile.do?id=20711#260,5,Prepositions used with verbs