拟合优度被定义为（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/50fe08c7b550458a9fd6f079be604b53.png"> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/9bb3c8437ea14207a3dec35c223efef6.png"> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/aedb567ec0934e3d9ef8a934f0118967.png"> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/5efc9dbadec84e28968d639bb2383a43.png">

在完备的结构式模型<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/c5ce3f82eaef4a8e9b78ac56100488c3.png" />中，外生变量是指( )。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/3d7fa1fd2a724a31a9dba12982dedd5b.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/c812517c51c44c5bb9f29c45b819050a.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/122d7aec5eda4dabbf983fabc83d73b7.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/d8ee965853364b7b9227f1cc83e46409.png" />

<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/4d6959efe5f94bb690c25c1a7f6cf7ec.png" />点在三向应力状态中，若<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/3b70ba8af50b4b4ea00548dd54c64647.png" />，则关于<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/4e33f2cc7385440cb6b016dd85db79ad.png" />的表达式有以下四种答案，正确答案是（ ）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/6fc49ba4cd4b4054aaf6cd6e92f5c678.png" />； B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/cc792d5eb3b5437692fd66a12aac7f09.png" />。 C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/e680eb44d5124e1999c29940899f2f4a.png" />； D: 0；

下列正确表示坐标系的是（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/4bb4378bbfcd4819855fe50706b1f263.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/fa0ed959ff384f8c91b6b3caca97e663.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/9eff58740cfe4d9dbadffe27f93ac4a6.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/1a25fccdb5b94032998d272c4fe12606.png" />

下列化合物有旋光性的是（ ） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/cf804a29b076488b9f56bb592d092f6f.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/7c02764f7e0740f19cd3d74d8ffbc232.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/3d95831adf704381891c84ae45dec25b.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202011/e8a6fe9e6da84c2badca12fbb45599e5.png" />