比旋光度测定中的影响因素有
A．温度
B．溶液浓度，光路长度
C．光源的波长
D．A+B+C
E．A+C
参考答案：E
We should realize that we can only achieve our goal if we are prepared to __ and learn from failure.
A．deal with
B．depend on
C．carry on
D．go with
求函数z=x2+xy+y2-4lnx-10lny的极值．
