Choose the correct answer to each of the following questions.

Many plants and animal species are now on the _______ of extinction.

Find the mistake in each of the following question. 

A novel is a story long enough to fill a complete book, in that the characters and events are usually imaginary.

Find the mistake in each of the following question. 

Developing new technologies are time-consuming and expensive.

Choose the correct answer to each of the following questions.

The computer has had an enormous _________ on the way we work.

Choose the correct answer to each of the following questions.

________ have enough apples, she’ll make an apple pie this afternoon.

Choose the correct answer to each of the following questions.

His letter is full of mistakes. He _____ the mistakes carefully before sending it.

Choose the correct answer to each of the following questions.

His letter is full of mistakes. He _____ the mistakes carefully before sending it.

Find the mistake in each of the following question. 

The earth is the only planet with a large number of oxygen in its atmosphere.