A British company has developed a camera that can detect(探测) weapons and hidden drugs, which is a great ______ for the security industry. A.breakthrough B.introduction C.principle D.conclusion 答案:A
在括号里选择合适的词语,使句子的意思更具体
有几个人坐在________的大树下乘(ch6ng)凉。
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A 高大挺拔
B 枝叶茂盛