Directions: In this section, you will hear three passages. At the end of each passage, you will hear three or four questions. Both the passage and the questions will be spoken only once. After you hear a question, you must choose the best answer from the four choices marked A), B), C) and D). Then mark the corresponding letter on Answer Sheet 1 with a single line through the centre.
Questions 16 to 18 are based on the passage you have just heard.
16. What does the passage say about ants?
A) They help farmers keep diseases in check.
B) Many species remain unknown to scientists.
C) Only a few species cause trouble to humans.
D) They live in incredibly well-organized colonies.
17. What do we learn from the passage about carpenter ants?
A) They are larger than many other species.
B) They can cause damage to people’s homes.
C) They can survive a long time without water.
D) They like to form colonies in electrical units.
18. What can we do to prevent ants from getting into our homes?
A) Deny them access to any food.
B) Keep doors and windows shut.
C) Destroy their colonies close by.
D) Refrain from eating sugary food.
Scientists have identified thousands of known ant species around the world. And only a few of them bug humans. Most ants live in the woods or out in nature, there they keep other creatures in check, distribute seeds and clean dead and decaying materials from the ground. (16) A very small percentage of ants do harm to humans. But those are incredibly challenging to control. They are small enough to easily slip inside your house, live in colonies that number in the tens of thousands to the hundreds of thousands, and reproduce quickly. That makes them good at getting in and hard to kick out. Once they settle in, these insects start affecting your home. In addition to biting ants, other species can cause different kinds of damage. (17)Some, like carpenter ants can undermine a home structure, while others interfere with electrical units. Unfortunately our homes are very attractive to ants because they provide everything the colony needs to survive, such as food, water and shelter.
So how can we prevent ants from getting into our homes? (18)Most important of all, avoid giving ants any access to food, particularly sugary food because ants have a sweet tooth. We also need to clean up spills as soon as they occur and store food in airtight containers. Even garbage attracts ants, so empty your trash as often as possible, and store your outside garbage in a lidded can well away from doors and windows.