◎ 题干
 单项选择。
There ______ a tree in front of the classroom last year, but there ______ now.
[     ]
A. is, isn't
B. isn't, is
C. was, wasn't
D. was, isn't
◎ 答案
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◎ 解析
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◎ 知识点
    根据n多题专家分析,试题“单项选择。There ______ a tree in front of the classroom last year, but there ______ now. [ ]A. is, isn't B. isn't, is C. was, wasn't D. was, isn't …”主要考查了你对  【系动词】  等知识点的理解和应用能力。关于这些知识点的“档案”,你可以点击相应的链接进行查看和学习。