Which one is right answer?and why?
Because of the Olympic Games________.
A. there has been a lot of new building
B. a lot of new building was completed
C. a lot of new building has been planned
D. there was a lot of new building
Which one is right answer? and why?Here is the whole article.
The Olympic Games will be held in our country in four years` time. As a great many people will be visiting the country the government will be building new hotels, an immense stadium, and a new Olympic-standard swimming pool. They will also be building new roads and a special railway line. The Games will be held just outside the capital and the whole area will be called "Olympic City". Workers will have completed the new roads by the end of this year. By the end of next year, they will have finishe work on the new stadium.The fantastic modern buildings have been designed by Kurt Gunter. Everybody will be watching anxiously as the new buildings go up. We are all very excited and are looking forward to the Olympic Games because they have never been held before in this country.

Question

Which one is right answer?and why?
Because of the Olympic Games________.
A. there has been a lot of new building 
B. a lot of new building was completed
C. a lot of new building has been planned
D. there was a lot of new building 
Which one is right answer? and why?Here is the whole article.
The Olympic Games will be held in our country in four years` time. As a great many people will be visiting the country the government will be building new hotels, an immense stadium, and a new Olympic-standard swimming pool. They will also be building new roads and a special railway line. The Games will be held just outside the capital and the whole area will be called "Olympic City". Workers will have completed the new roads by the end of this year. By the end of next year, they will have finishe work on the new stadium.The fantastic modern buildings have been designed by Kurt Gunter. Everybody will be watching anxiously as the new buildings go up. We are all very excited and are looking forward to the Olympic Games because they have never been held before in this country.

Answer

Good question... 

I agree with Peachy. 
Peachy's explanation of the verb tenses is correct, which means A, B and D are not correct because the article tells us that a lot of building has only just begun or will begin soon. 

In the article, the word "building" is a gerund. 
A gerund functions as a noun and is formed from a verb. 
To make a gerund, you add "-ing" to the verb. 

Other similar sentences could be: 
Because of the Olympic Games, a lot of new planning was needed. 
Because of the Olympic Games, a lot of new designing has been done. 
Because of the Olympic Games, a lot of new scheduling was required.

Answer

If you mean building as the action and not the physical thing, then it makes more sense (although I'm not sure why it says "new building" - I agree "new construction" sounds more comfortable).

The article tells us the building hasn't happened yet, so A, B and D don't fit - the building is a past event (in A, also in the present). So only C fits.

Answer

我觉得C是对的，因为从题意可知，由于奥运会才会有那么多得建筑，所以建筑还未完成，用was不好。A表示已经有了很多建筑物，还没建则呢没可能会已经有了?所以C最正确:P个人见解，仅供参考

Answer

None of them are correct.

If you meant "a lot of new buildings" or " a lot of new construction", I still can't give you an answer without context.

Now with the context. 'A' is correct.
In my opinion they're all incorrect. The word "building" is used incorrectly here. 
As to the grammar, since they will have finished stuff later, then it means there has been a lot of construction already.
These are things you MUST learn to figure out by yourself if you want to make good progress.

Answer

d is right i think