下列化合物有旋光性的是( )。
A:
B:
C:
D:
A:
B:
C:
D:
举一反三
- 已知物体的主、俯视图，左视图正确的是（ ）。 A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201905/3930fea847ba4492944ddb365a59ad61.png" border="0" vspace="0" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201905/8c60c5d1b6634256b2ef9a91dac8488e.png" border="0" vspace="0" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201905/c0b01d9bd70846c0a833771f3e1329f0.png" border="0" vspace="0" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201905/f4f8a566f2de4d289c53bb491395d1fe.png" border="0" vspace="0" />
- 由角系数性质，任意两表面间的角系数有下列关系（）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/8fe9f71498f04232b7d9626ea192f5d5.png" border="0" vspace="0" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/d2b63ba506614bfab0e0d91b5a62b9bd.png" border="0" vspace="0" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/f88fb5553ef147e996473ea8d738144e.png" border="0" vspace="0" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/3bb42a34fc7943abb899e6ad38246778.png" border="0" vspace="0" />
- 下列草图用旋转特征工具不能生成实体的是（）。1、<img width="50" height="100" src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/0c0ba8db9acf4933a0e5df79d9dddaea.png" border="0" vspace="0 2、<img width="60" height="100" src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/341180a27efb4211b512ab4269ae865a.png" border="0" vspace="0 3、<img width="80" height="100" src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/97007edcda2644d78d09b1089aa9af7a.png" border="0" vspace="0 4、<img width="80" height="100" src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/6a56890b40874f78a8df75419e014d27.png" border="0" vspace="0
- 如图所示，离心机通风机借集流器从大气中吸入空气。若插入盛水容器的玻璃管中的水上升高度为h，则通风机流量<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/b90be52d519d4880a560e59df52dd29c.png" />=（）。<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/dca2260bbd5c4051b28bbb87ae1d6de9.png" /> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/7b4225635cfe41e28af202418785be8d.png" border="0" vspace="0" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/05404534275442c597194a44ee9f46f7.png" border="0" vspace="0" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/5509cc1799e54c64a7a11a7f37417710.png" border="0" vspace="0" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201909/307ded8ddb2c486d935b6bc79faa7688.png" border="0" vspace="0" />
- 以下那些操作可以新建一个背景？ A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/40aa135f5f0a475f971257bb827504fb.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/9307bb62780f4beb9816a80655aa869f.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/4c22f5c8020040beaa0fe566345b7eb9.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/e66c4f191e944062b31d06d70642aa3f.png" />