Question

閱讀下面短文，然后根據短文內容選擇最佳答案。 　　Put an ice cube from your fridge into a glass of water．You have a piece of string 10 centimetres long．The problem is to take out that piece of ice with the help of the string．But you must not touch the ice with your fingers． 　　You may ask your friends to try to do that when you are having dinner together．There is a saltcellar on the table．You must use salt when you carry out this experiment． 　　First you put the string across the piece of ice．Then put some salt on the ice．Salt makes ice melt．The ice round the string will begin to melt．But when it melts, it will lose heat．The cold ice cube will make the salt water freeze again． 　　After a minute or two you may raise your piece of ice! 　　This experiment can be very useful to you．If, for example, there is ice near the door of your house, you must use much salt to melt all the ice．If you don't put enough salt, the water will freeze again． (1) We must use ________ when we carry out this experiment． [　　] A． a fridge B． some food C． a table D． some salt (2) How long will it take to carry out this experiment? [　　] A． More than three minutes． B． Five minutes or so． C． Only one or two minutes． D． About ten minutes． (3) What is the purpose of this experiment? [　　] A． Put the ice cube into the glass of water with the help of the string． B． Take out the ice cube in the glass of water with the help of the string． C． Take out the ice cube in the glass of water with your fingers． D． Put some salt on the ice cube and then put the string across it． (4) How many things at least are used in this experiment? [　　] A． Three． B． Four． C． Six． D． Seven． (5) We can learn something about ________ from the passage． [　　] A． physics and biology B． biology and science C． chemistry and biology D． physics and chemistry

Answer 1

答案：1．D;2．C;3．B;4．B;5．D;