Canals are watercourses constructed to improve and extend natural waterways. They are generally built to facilitate transportation, but from the beginning they have been used for many additional purposes including draining swamps, irrigating land for cultivation and promoting economic development.
- Reading Practice Test 74 from The Collection of TOEFL Reading Comprehension
- Reading Practice Test 67 from The Collection of TOEFL Reading Comprehension
- Reading Practice Test 66 from The Collection of TOEFL Reading Comprehension
- Reading Practice Test 65 from The Collection of TOEFL Reading Comprehension
- Reading Practice Test 64 from The Collection of TOEFL Reading Comprehension
Canals are often classified by the size of vessel they can accommodate. Some small local canals, which are able to float only 100 – to 300 – ton boats or small rafts of timber. may be only 3 feet deep. Major barge canals generally range from 6 to 9 feet in depth, and some are as much as 10 or 12 feet deep. These canals can carry 1.350 – to 2. 000 – ton crafts. Ship canals are 25 feet or more deep and are capable of accommodating large vessels in the seagoing class.
Canals may also be classified as either water – level or lock canals. Water – level canals do not vary in height along their courses. The best known of these is the Suez Canal, which is at sea level. Lock canals, which include most modern waterways, contain locks, or special devices for raising and lowering boats along their courses by changing the depth of the water. Each lock is a stretch of water enclosed by gates at each end. After a boat enters the lock, water is let in or drained out until it reaches approximately the same level as the water ahead.
1. What does the passage mainly discuss?
(A) How canals are constructed
(B) Common types of canal boats and barges
(C) The world’s largest canals
(D) How canals are used and classified
2. The canals mentioned in the second paragraph are grouped according to their
3. The word “accommodating‘ in line 9 could best be replaced by
4. What is the purpose of a canal lock?
(A) To keep out boats that are too large for the canal
(B) To measure the tonnage of canal boat
(C) To load and unload the cargo
(D) To change the depth of the water
5. The Suez Canal is mentioned as an example of a
(A) modern canal
(B) water – level canal
(C) lock canal
(D) irrigation canal
Some of the most beautiful caves are formed in glaciers. Streams of melting ice and snow tunnel through the glaciers the same way that water from a faucet melts its way through an ice cube. Water from the surface drips down through cracks, hollowing out the tunnels and decorating the caves with crystal icicles. The smooth walls and floors are so glasslike that pebbles frozen six feet deep can easily be seen. Crystal – clear icicles draping from the ceilings flash blue – green, as though they were carved from precious jewels instead of ice.
Although most of the cave ice in the United States is found in lava caves, there are a number of limestone ice caves as well. Some people believe that this ice was formed thou -sands of years ago, when temperatures were much colder than they are today. Others think that the cave ice broke off from the ancient glaciers as they spread over the country.
Today many cave scientists have another idea. They believe that cold water sinks down through cracks into these caves until the temperature is chilly enough to freeze the water that seeps in. The ice that forms keeps the cave cool, and that helps build up still more ice. Many caves become covered with so much ice that no one knows just how thick it is. In some, such as Crystal Falls Cave in Idaho, there are frozen rivers and even frozen water -falls. Native Americans and early settlers used to store food in these underground refrigerators and chip our blocks of ice to melt for drinking water.
1. What does the passage mainly discuss?
(A) Characteristics of glaciers
(B) Uses for ice caves
(C) The origin of cave ice
(D) Where glaciers can be found
2. The word “its” in line 2 refers to
3. The word draping” in line 5 closest in meaning to which of the following?
4. The author compares icicles to precious jewels based on which of the following?
(C) Method of formation
5. Where is most of the cave ice in the United States found?
(A) In lava caves
(B) In ancient glaciers
(C) On cave ceilings
(D) In cave cracks
6. According to many of today’s cave scientists, what causes ice to build up in caves?
(A) Rivers and waterfalls supply water
(B) Icicles accumulate on the ceilings
(C) Cave ice breaks off glaciers
(D) Cold water seeps in and freezes
7. It can be inferred from the passage that the early settlers in the United States appreciated the ice caves for their
(B) beautiful interiors
(C) historical value
(D) precious gems