1编号：41740题型：填空题测试正确率：46.76%
用不定冠词“a”或“an”填空。 Dictionary is ____ useful tool(工具)in learning(学习) English.
2编号：41739题型：填空题测试正确率：34.52%
用不定冠词“a”或“an”填空。 There is ____ “m” and ____ “n” in the word “number”.
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