Wednesday, September 14, 2011

Thursday, May 28, 2009

How many types of adverbs are there?

There are several types of adverb:
  • Adverb of manner 
  • Adverb of place 
  • Adverb of time 
  • Adverb of frequency 
  • Adverb of degree
There are different places where you can put the adverb.

ADVERBS OF MANNER - these answer the question how?

This adverb usually comes after the direct object or if there is no direct object, after the verb:
She speaks Italian beautifully.
He works well.
You must drive your car carefully
Eat quietly.

ADVERBS OF PLACE - these answer the question where?

This adverb usually comes after the object, otherwise after the verb:
We saw you there
We were sitting here
We looked everywhere.
Note: somewhere, anywhere, follow the same rules as some and any:
Have you seen my glasses anywhere

I'm sure I left them somewhere
I can't find them anywhere.

ADVERBS OF TIME - these answer the question when?

This adverb usually comes either at the very beginning of the sentence or at the end.
Afterwards we decided to go by car. I've done that journey before.
Note: yet and still - yet should be placed at the end of the sentence.
Still should be placed before the verb, except with the verb 'to be' when it comes after.

We haven't started yet
He still wears old-fashioned clothes. 
She is still a student.
Compare these two sentences:
The train still hasn't arrived. 

The train hasn't arrived yet.

ADVERBS OF FREQUENCY - these answer the question how many times?

This adverb comes after the verb 'to be':
She is always honest.

Comes before simple tenses of all other verbs:
They sometimes spend the whole of Saturday fishing.

Comes after the first auxiliary in a tense consisting of more than one verb:
I have often wondered how they did that. 

I can sometimes go without food for days.
Note: with 'used to' and 'have' the frequency adverb is usually placed in front:
We always used to look forward to the school holidays. 

He never has any trouble with his old car.

ADVERBS OF DEGREE - these answer the question to what extent?

This adverb can modify an adverb or an adjective and comes before the word it modifies:
The bottle is almost full, nearly empty. 
They should be able to pass their exams quite easily.
The following adverbs of degree can also modify verbs: almost, nearly, quite, hardly, scarcely, barely, just.
They follow the same pattern as frequency adverbs in terms of where they are placed:
I quite understand. 

We had almost reached the hut when the rain started. 
I am just beginning a new course.

INVERSION

If you begin a sentence with one of the following, the normal word order changes - the verb comes first followed by the subject:
never, seldom, scarcely ..... when, no sooner ..... than, nowhere, in no circumstances, on no account, only then, not only.

Seldom has one century seen so many changes. 

No sooner did we hear the results when there was a knock at the door.
Never would I be persuaded to buy a secondhand car.
Usual word order with different adverbs: MANNER PLACE TIME
She sang beautifully in the concert hall last night.

Wednesday, May 27, 2009

Solar Energy – Nature and Composition

Sun is the main source of energy on the Earth. Life sustains on the Earth because of electromagnetic radiations and without the Sun, the Earth would have 270 degree Celsius of equilibrium temperature. The Earth emits an equal amount of energy as it receives from the space, so there is a heat balance on the Earth. The Sun pours a huge quantity of electromagnetic energy on it and everything on the Sun is the source of these radiations. The Sun emits over a wide range of electromagnetic radiations. The incident solar energy, mainly, is in the visible part of the solar spectrum, while the key part of the radiation lies in the infrared region.

In eight minutes the radiation emitted from the Sun gets to the Earth. The ray which lightens up the surface of the Earth is the visible light, also known as white light, which is the continuous mixture of colors. This light when passed through the prism disperses into a band of seven colors. The energetic part of the spectrum is the ultraviolet radiation, which is undetectable having shorter wavelengths compared to white light. Those of ultraviolet radiations having extremely shorter wavelengths are filtered in the outer atmosphere by the ozone layer.

Thermal radiations, as they are referred to, are the invisible infrared radiations having longer wavelengths compared to those of white light. Mostly, the incoming infrared rays are filtered by the atmosphere of the Earth containing water vapors. The opacity of the atmosphere, chiefly, is responsible for maintain the warmth of the Earth, although the surface of the Earth is rather transparent to the longer wavelengths in the infrared region.

Besides optical radiations from the Sun, solar energy spectrum contains radio and X-rays also. Hotter bodies emit a larger wavelength of spectrum. Intense radio waves have been observed over the Sun's surface at 330 MHz having wavelength of about one meter. The studies of wavelength in the X-rays component of the electromagnetic spectrum are made by specially designed sensitive imaging techniques.