Mostly from Asian countries, they stay for anything from a few weeks to a few years or more, studying at language schools, colleges and universities.

They refers to

New Zealand can offer good homestay accommodation, a clean and beautiful environment and a reasonable cost of tuition. These factors attract an ever-increasing number of overseas students, accounting for millions of dollars in revenue for New Zealand.

These factors refers to ...

This quiz concerns cohesion that is achieved by the use of pronouns to refer back to a noun that has been already been introduced. As an example, the following sentence doesn't read well because the pronoun has not been used: John was late for class again, so the teacher put John in detention. Much better is: John was late for class again, so the teacher put him in detention.

What is the referent of the pronoun him?

The Alaska pipeline starts at the frozen edge of the Arctic Ocean. It stretches southward across the largest and northernmost state in the United States, ending at Linea remote ice-free seaport village nearly 800 miles from where it begins.

It refers to ...

The railroad was not the first institution to impose regularity on society, or to draw attention to the importance of precise timekeeping. For as long as Line merchants have set out their wares at daybreak and communal festivities have been celebrated, people have been in rough agreement with their neighbors as to the time of day. The value of this tradition is today more apparent than ever.

The phrase "this tradition" refers to ...

Over time beneficial traits and characteristics that promote survival will be kept in the gene pool while those that harm survival will be selected against. Therefore, this natural selection ensures that a species gradually improves itself over an extended duration of time. On the other hand, as a species continues to 'improve' itself, it branches out to create entirely new species that are no longer capable of reproducing together.

The word 'those' in paragraph 1 refers to ...

We were able to walk along the kangaroos and wallabies. We were even allowed to touch them and to feed them.

…. allowed to touch them and to feed...

The word them in paragraph 3 refer to ....

Early artists drawing these animals accomplished a monumental and difficult task. They did not limit themselves to the easily accessible walls but carried their painting materials to spaces that required climbing steep walls or crawling into narrow passages in the Lascaux complex.

The word they refers to ...

The hippopotamus is the third largest land animal, smaller only than the elephant and the rhinoceros. Its name comes from two Greek words which mean “river horse.” The long name of this animal is often shortened to the easier to handle term “hippo.”

The possessive “its” in line 2 refers to ...

Because this dollhouse is almost 300 years old, it is historically important.

The furnishings are noticeably different from their modern counterparts.

The tiny chest and dresser still have their original hardware.

The family that owns the house loaned its treasure to the library.

The family wanted their friends to see the house.

As a child, Aunt Livia often played with her dollhouse.

In the 1920s, a society woman created a dollhouse and Carrie Stettheimer’s artist friends contributed their talents to making it special.

When the team scored a touchdown, the crowd threw (its, their) hats in the air.

Neither Carmen nor her sisters have bought a gift for (her, their) brother.

Some of the equipment was still packed in its containers