问题 判断题

苯芴酮比色法测定锡时,在弱酸性溶液中四价锡离子与苯芴酮形成微溶性的橙红色络合物,应在保护性胶体存在下与标准系列比较定量。

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填空题

词汇运用。

     During the Second World War, John's family didn't have a washing machine.Therefore,     1   (keep)

clothes clean became a problem for them. Before long, a family friend decided    2    (join) the army and

his wife was going with him. John's family told them that they could take care of their furniture while they

were away. To the     3   (family)surprise, the friend suggested they should use his Bendix washing machine.

 "It would be better for it to     4   (use), rather than sitting    5    (quiet)," he said.

     Young John helped with the washing, and he developed a deep love of the old, green Bendix.     6  

(Late), the war ended and the family's friend returned. When he came to take the machine away. John

became very sad. His mother saw this and said to     7    (he), "Son, you must remember that machine

didn't belong to us in the   8    (one) place. It was a gift for us to be able to use it for such a long time. So,

instead of     9   (be) sad about the loss, let's be grateful that we    10    (be ) able to use it at that time."

     We have all experienced loss: loss of people and things. However, if we see the thing we     11   (lose) as

a gift that we were given for a time, maybe the sad     12   (memory) will change into     13   (thank ) ones.

1.______ 2.______ 3.______ 4.______ 5.______ 6.______7.______

8.______ 9.______ 10.______ 11.______ 12.______ 13.______

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