Read and translate text 2 using a dictionary if necessary.

CAISSONS

The word "caisson" is derived from the French word meaning "case". In civil engineering a caisson may be defined as a large watertight box used to excavations of foundations and the construction of substructures. It is an integral part of the structure. This box or caisson may be "open", without a bottom or may be excluded by air pressure, and the box becomes a pneumatic caisson. This was a development of the earlier cofferdam — a wall within which, after pumping out the water, it was possible to excavate and then build the base of the pier in the dry. The ordinary open caisson consists of a box with cross walls. Sometimes the caisson is constructed of reinforced concrete or a steel cylinder.

18. Say if its true or false. Use the following expressions: "That ' s right" or "That ' s true", "That ' s wrong" or "According to the text…".

1. The word "caisson" isn't of English origin.

2. In construction engineering a caisson is defined as a small watertight box applied to exclude water during the assembly work.

3. This box may be with or without a bottom.

4. If the box is inverted, the water may be excluded by water pump.

5. The common open caisson has usually a box with cross walls.

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