1. What nice weather it is!

1-2. What a nice weather it is!
(Which one is right?)

2. What a tall building it is!
2-2. How tall the building is!
2-3. How tall a building is!

(Which one is the same as #2?
# 2-2 or #2-3? What is the meaning of #2-3)

3. What a tall dog it is!
What a big dog it is!
How tall the dog is!
How big the dog is!
(Which one is commonly used? Are all used commonly?)

4. She speaks good English.
She speaks a good English.
(Which expression is correct? Do we have to use 'a' or not before good English.)

1. What nice weather it is!

1-2. What a nice weather it is!
(Which one is right?)
The first one is correct.

2. What a tall building it is!
2-2. How tall the building is!
2-3. How tall a building is!
(Which one is the same as #2?
# 2-2 or #2-3? What is the meaning of #2-3)
2-2 is the same as 2. 2-3 is not correctly written, although you might write, "How tall a building it is!"

3. What a tall dog it is!
What a big dog it is!
How tall the dog is!
How big the dog is!
(Which one is commonly used? Are all used commonly?)
The second and fourth ones are most common. "Tall" is not usually used to describe dogs.

4. She speaks good English.
She speaks a good English.
(Which expression is correct? Do we have to use 'a' or not before good English.)
The first one is correct. The word "a" should not be used in this context.

1. Both sentences are correct, but they have slightly different meanings.

- "What nice weather it is!" expresses a general appreciation for the current weather. It is a statement about the weather itself.

- "What a nice weather it is!" expresses surprise or emphasis on the fact that the weather is nice. It is a statement about the speaker's perception or reaction to the weather.

2. The correct sentence is "How tall the building is!"

- "What a tall building it is!" is grammatically correct but conveys surprise or emphasis on the building's height.

- "How tall a building is!" is not commonly used. It is grammatically correct, but it does not convey the same emphasis or surprise as the previous sentence.

3. All of the sentences are commonly used, but they have different meanings:

- "What a tall dog it is!" emphasizes the speaker's surprise or admiration for the dog's height.

- "What a big dog it is!" emphasizes the speaker's surprise or admiration for the dog's size in general.

- "How tall the dog is!" is a statement about the dog's height, without any particular emphasis.

- "How big the dog is!" is a statement about the dog's size in general, without any particular emphasis.

4. The correct expression is "She speaks good English."

- "She speaks a good English" is incorrect because "English" is an uncountable noun and does not require an article like "a" before it. We use "good" as an adjective directly before the noun "English" without an article.