Choose the correct answer to complete the sentence. "Deforestation is one of the biggest environmental______ the ecological balance in the world"

It was suggested that Tom studied the document more thoroughly before attempting to pass the exam

The Egyptians first discovered that drying fruit preserved it, made it sweeter and improvement its flavor.

The biologist found some pollutants, a little of which can be considered very harmful to fish and other living organisms in the river.

Consequently the kit fox is an endangered species, wildlife experts in the California desert are using carious methods to protect it.

When you passed the town hall clock, did you notice what time was it

The National Basketball Association will not let any athlete to continue playing in league unless he submits voluntarily to treatment for drug addiction.

It was after shortly microscopes were introduced at the beginning of the seventeenth century that micro organisms were actually sighted.

................. money you gave me is not enough to buy ..................bicycle. 

I work in a large office with about thirty other people, most of whom I know quite well enough.

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.

It is time the government helped the unemployment to find some jobs.

Vaslov Nijinsky achieved world recognition as both a dancer as well as a choreographer

He usually travels to..................Philadelphia by.................. train. 

“I’m sorry you failed the test.” “Frankly, I wish I ____ harder.” 

Some snakes have hollow teeth are called fangs that they use to poison their victims

Yogurt contains a higher percentage of lactic acid than another fermented milks, and it is rich in B-complex vitamins.

Since the average age of families has fallen, therefore more and more women have been able to join the labor force

The peasant’s wife, who have been married for four times, has just had her third baby

Rita plays .......... violin and her sister plays .......... guitar. 

The amount of books in the Library of Congress is more than 58 million volumes