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问题 多项选择题

以下（）属于CWDM工作波长的范围

A、1470~1510nm

B、1510~1550nm

C、1550~1590nm

D、1590~1630nm

E、1630~1670nm

答案

参考答案：A, B, C

选择题

His teacher told him that since his parents were working abroad , either his grandparents or one of his uncles ______ allowed to come to the parents’ meeting .

A．was

B．were

C．are

D．is
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选择题

下列加点的“焉”字意义和用法相同的是 (    )

A．于乱石之间择其一二扣之，硿硿焉

B．古之圣人，其出人也远矣，犹且从师而问焉

C．焉有仁人在位，罔民而可为也

D．积土成山，风雨兴焉 E.王若隐其无罪而就死地，则牛羊何择焉  F.夫子言之，于我心有戚戚焉
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