Scientists sent ............ expedition to ............ Mars during .......... 1990s. 

I found it difficult convincing the ticket inspector that I had lost my ticket, but he believed me in the end

Before the invention of the printing press, books have been all printed by hand.

The waste from the chemical factory is extremely .......

Scuba diving is usually carried out in the ocean in that people can explore the underwater world.

It’s been brought to my attention that there has been a number of thefts from the office.

I wish you ______________ making that noise. It's bothering me. 

One of the four underlined parts marked A, B, C, D in each sentence is not correct in standard English. Identify them: 

If he weren’t too old, he would apply to the job as a reporter. 

A light year is the distance that light travels in one year calculated by using the speed of 186,284 miles the second as a base

Bells told people of happy vents, such as weddings and born or, sometimes had to announce unpleasant events such as a death.

Once the scientist had figured out the precise path of the comet, he is finding that he was able to predict its next appearance.

............. winter is usually cold, but .................. winter of this year is warm. 

Mr. Smith is going to buy a new Japanese car, doesn’t he ?

In the early twentieth century, there was considerable interesting  among sociologists in the fact that in the United States the family was losing its traditional roles.

The two kilograms of drugs which the police have seized is only the tip of the iceberg. They fear that far more are being smuggled and distributed.

While the sun is the major source of ultraviolet rays, it is not the source only

If I had known that you couldn’t eat eel, I ____ bought it. 

The early periods of aviation in the United States was marked by exhibition flights made by individual fliers or by teams of performers at country fairs

The development of professional sports in the United Stated dates back to nineteenth century.

If the airplane ticket wasn’t expensive, I could fly to Singapore for my holidays.

Although apples do not grow during the cold season, apple trees must have a such season in order to flourish.