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A．The speaker was an expert on modern literature.B．The speaker had to give a speech wi
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The Advantages and Disadvantages of Buying Lottery
Tomato Ripening
Tomatoes give off minute quantities of ethylene gas which is active in starting the natural ripening process. If left to nature, however, the tomatoes ripen in a random way. The trickled ethylene gas process of tomato ripening consists of exposing the tomatoes to a low concentration of ethylene gas under controlled temperature conditions in a special tomato-ripening room. This treatment initiates and controls the speed of the natural ripening and colouring process in the tomatoes.
Controlled ripening and colouring enables the grower to market tomatoes of more uniform. colour and quality than is possible with green or fieldripened produce. Timing of harvesting and marketing may, within limits, also be regulated by the use of controlled ripening and colouring in order to achieve maximum returns and make the best use of labour and equipment.
Ripening Conditions
All fruit must be mature green at harvest for controlled ripening to be successfully carried out. Relative humidity does not appear to be of great importance in the tomato-ripening process. Little moisture loss from the tomatoes occurs during the ripening process due to the relatively impermeable nature of the tomato skin. Ripening time will depend on the ripening temperature range, however, ripening temperature above 24℃will result in poor colour development with yellow or orange fruit rather than red. The heating and cooling capacity should be such that the tomatoes can be brought to the recommended ripening temperature within 24 hours.
Room Size and Construction
For efficiency and convenience in operation, on-farm, tomato ripening rooms are usually sized to accommodate the normal daily tomato pick during the peak harvest time. The room capacity is generally in the range of two to ten tonnes of tomatoes. However, larger rooms may sometimes he installed. Since the average ripening time is three or four days, tile provision of multiple rooms on the farm is generally desirable.
Air Circulation and Ventilation System
Fan-forced air circulation is required tbr adequate and uniform. temperature control and ethylene gas distribution in the ripening room. An air circulation rate of two room air volumes per minute is recommended for good results. This is equivalent to around 480 cubic metres of air per hour per tonnes of tomatoes. At the recommended heating or cooling capacity of 0. 6 to 1.2kw per tonne of tomatoes, this gives an air circulation rates are necessary to limit variations in temperature in different parts of the room to acceptable levels and to achieve an adequate rate of heating or cooling of the tomatoes.
The ventilation system circulates the room air continuously, introducing a small proportion of fresh air and exhausting a similar amount of air at the same time. This prevents a build up of ethylene gas in the room and also removes carbon dioxide produced by the fruit during respiration. If this car- bon dioxide were allowed to build up to too high a level in the room atmosphere, it would interfere with the ripening process.
Temperature Control System
The temperature of tomatoes in the ripening room has a great influence on the ripening process. In fact, the product heat load usually represents around 80% of the total heat load. The remainder is due to heat transmission through the exterual walls of the room anti the fresh air exchange rate. In some cases, both heating anti cooling are required to maintain the room temperature within the required range. The time required for ripening can be reduced to some extent by increasing the temperature. Reverse cycle air-conditioners are successfully used for both heating and cooling in tomato-ripening rooms where humidity control does not
Section A
Directions: In this section, you will hear 8 short conversations and 2 long conversations. At the end of each conversation, one or more questions will be asked about what was said. Both the conversation and the questions will be spoken only once. After each question there will be a pause. During the pause, you must read the four choices marked A, B, C and D, and decide which is the best answer.
听力原文：W：I intend to buy some fruit for the children，These apples and bananas seem to be in season．I'll get two dozen of each．
M：I hope they're as good as they look．
Q：What does the man mean？
(12)
听力原文： It was years since I had visited my hometown and I was determined to enjoy my stay. I went to see my old friend, Tom Clark who, among other things, was a in ember of the Local Council. At the time Tom was busy making arrangements for a distinguished writer to give a talk on modem literature at the town library. As the subject interested me a great deal, I gladly accepted Tom's invitation to go with him.
Tom was going to introduce the guest speaker and that evening we went to the library to meet him. Since he had not yet arrived, I left Tom and went into the Reading Room where a large audience had already gathered. I was disappointed to find that I did not know a single person there. Just before the talk was due to begin, I saw Tom waving to me from the doorway. I went to him immediately, as he looked very worried. He explained that he had just received a telephone message from the writer's secretary. Our guest speaker had missed the train and would be unable to come!
While we were talking about the problem, Tom suddenly asked me if ! would mind acting as speaker. 1 hardly had time to think 'about the matter when I found I was being led into the Reading Room to address the waiting audience!
(34)
A．Ask the operator to put you through.B．Check the phone number and call again.C．Tell t
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