Bats have long been one of the most frightening creatures in the animal kingdom. Many pop culture association with them are related to witches     1     (put) evil curses on innocent individuals.     2     these associations are complete misunderstandings; these flying mammals do have a dark side as a dangerous disease earner. They can cany a number of     3     (fate) diseases such as rabies and more recently Ebola. This has led many to wonder why we should care about them. However, there is no denying the fact     4     bats play a significant role in maintaining a balanced ecosystem. Up to now, many organic farmers     5     ( learn) about the benefits of having bats nearby to help manage the amount of pests that show up without pesticides. One brown bat—about the size of a human thumb can consume about 600 mosquitoes and other unwanted insects with in     6     hour. The United States Geological Survey estimates that bats’     7     ( contribute) to pest management save the country at least 3. 7 billion dollars per year.     8     them, we would be likely to experience a dramatic drop in food production. What’s more, bats are also of great importance to     9     ( various) of plant species that are preferential to its pollination. Otherwise, these plants would decrease their ability to reproduce by at least 50 percent. Therefore, we need them more than most of     10     (we) imagine.

I paid a visit to Tibet to observe Tibetan antelopes. While     1     (watch) them move slowly across the green grass, I was reminded of their bad old days.

During the 1980s and 1990s, they were shot and killed     2     (illegal) by hunters to make profits. To make things even     3    (bad), their habitats were destroyed to make room for new roads and     4    (railway). As a result, antelopes became     5     endangered species.

In order to change this situation, the Chinese government took some measures,    6     made a difference. For example, bridges and gates     7     (add) to let the antelopes move easily and keep them safe from cars and trains. Besides, many volunteers watched over the antelopes day and night    8     (prevent) them from being attacked.

These measures prove to be     9     (effect). Its population has recovered and in 2015, the Tibetan antelope was removed     10     the endangered species list. The government, however, intend to continue the protection programmes because the threats to the Tibetan antelope have not yet disappeared.

Many animals migrate at certain times of the year for various reasons. Of all the mass    1    (migrate), that of the North American monarch butterflies is one of the most wonderful. Every autumn, they begin    2    long and difficult journey. Somehow they manage to travel around 4,000 kilometres south and find their way     3    California or Mexico, where they will spend the winter. Scientists have found out that the monarch is able to tell the time of day and use its eyes     4    (measure) the position of the sun,    5     allows the butterfly to determine the way to go.

The solution to the mystery of the monarch’s amazing ability comes at a time when it is in serious trouble, and its population     6    (crash) by as much as 90 per cent in the last few years. Human activity is the main reason. In many of the places where the butterfly can     7    (find), people are destroying the natural environment by     8    (cut) down trees and using chemicals that kill the plants that monarch caterpillars eat.     9    (fortunate), people have been aware of the problem and working together to protect butterflies. The more we know about the butterflies, the     10    (great) the chance they will survive.