已知函数f(x,y)=x+y+xy,曲线C：x2+y2+xy=3，求f(x.y)在曲线C上的最大方向导数。
参考答案：
肛周癌最主要的转移部位是（）。
A.肝脏
B.肺
C.骨
D.肠系膜根部淋巴结
E.腹股沟淋巴结
John gets up early from Monday to S 1 , because he must go to school before 7:30 on weekdays(工作日) and go to the D 2 Club at 8:00 on Saturday mornings. He draws very well. He usually goes to the b 3 to look at the new books on Saturday afternoons, and after supper he watches TV until(直到) m 4 .
He doesn’t get up early on Sundays. John’s parents b 5 work on Sundays. John always watches TV after he gets up. Then he usually goes to KFC to have a h 6 and some juice for lunch. After that, he goes back home and b 7 to play computer games until his parents come back. He does his homework after supper. He usually has a lot of w 8 homework, so he must s 9 three hours on it. He usually goes to bed at about 11:00 p.m. on Sundays. He often complains(抱怨) he has too m 10 homework to do.
