下列手性碳原子为S构型的是（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/f26e98748b5f4febb87f5f729fa7e183.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/bddff733265d496783fc62fe08ae1bd7.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/be3096e7d3c345e2986ebacb04570b51.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/43a2967860564661ba5826a73a06629e.png" >

计算根轨迹渐近线倾角的公式为（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/608af0d299964c8f8821188092a56985.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/61795bdbc94c4921a02437814d1c0e29.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/6742e5f09f104644a3cf9be07ba7bdbd.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/477de697b8804d4ab36159a175ed07d9.png" >

下列化合物中，不具有极性的是（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/547b09efddc44eafa464beb5043142a7.png"> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/042b473209bc447b8f7914e4efe318d2.png"> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/60e6fcf97d024d519962631efc7a0e83.png"> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/b06bf6679a754656b24920d3a7c120a0.png">

设积分环节的传递函数为G(s)=<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/2428288e967b4a34ade338e5ea5c6ce0.png" >，则其频率特性幅值A(ω)=（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/33a8b22368e4429585bd402fd07fd717.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/492828f883b74680b8b22570ec3522cf.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/0f44b2548a3c424eaa326c2bf10bece6.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/b93eaefa6dd04794949e3987d24a0991.png" >

一盒产品中有<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/2cefaaf8bcb54c61977cecb4f0e40dea.png" >只正品，<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/65c8182d811f448784675cc993c132d2.png" >只次品，有放回地任取两次，第二次取到正品的概率为（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/73a908d0e00e4b44b0f7c78fe3c62154.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/f36521dfc9c64099b22f506146ac867d.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/4c42ae8aa5544a68a018618378bda287.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/201912/f7ca6abeab84438095bee512a092be80.png" >