配制pH≈7的缓冲溶液，应选择( ) A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/f91db91d906d4648a281e7e2414fecf4.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/d788ac460faf40348a1c3ad467417dd9.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/10b2abc3968d46fd8a7e9c276d6f0b19.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/cf120ba897744b3b9684f0365ded361e.png" />

设A=<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/bc546fc03fdb4ba3b7e6b144b6371d7f.png" />，B=Р(Р(A)) 下列（ ）表达式不成立。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/6e615703da60435893f9e9a9273e12e5.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/64c831067d054e71a6c76f43849d450d.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/72023a5250e44c12b98923044194f13d.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202002/c48e039a739c4502830eee7ae0ac1678.png" />

下列极限中结果等于e的是（ ）. A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/38da1b07f5c0405ea6707c9e6594b6a5.png"> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/eb7113c864f6405080daa91020fb9b6c.png"> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/4513ad5298554e2eb426e127192851d8.png"> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201910/9f89daefa1f445e295834ce3daac84cf.png">

网络函数<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202003/058dbbb5ab294d2980b41cd68dc78e69.png" />，其相应的单位冲激响应<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202003/efd689742f00449b818fd884bf9fd2cf.png" />为（ ） A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202003/571d5a5173d64731a7a1ed5c3ffaf403.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202003/b923d3ac7e9743c68ad701c170b784b4.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202003/d3c454406cd94e97a23806c9ba83d4e0.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202003/159fc59d34794c2b9f24f1ddbc368a14.png" />

下列离子属于9~17电子构型的是( )。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/98d5d4b38f664003989388c34b412dae.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/5d447bd56a6a4e5c899da3611c5592c3.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/c34f43d2aa684eac93ea994d37780085.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/0048373ac18e4dbebaeb3ad4687aacb3.png" />