某企业决定在武汉设立一生产基地，数据如下表。利用重心法确定该基地的最佳位置。假设运输量与运输成本存在线性关系（无保险费）。
参考答案：
解：X=（800*2+900*3+200*5+100*8）/（800+900+200+100）=3.05
Y.（800*2+900*5+200*4+100*5）/（800+900+200+100）=3.7
所以最佳位置为（3.05，3.7）。
| 完型填空。从每题的三个选项中选出可填入相应的空白处的最佳答案。 |
| Once a rich woman invited Martin Brown, a famous singer to sing for her friends. But she 1 him to have dinner with them. She told him to eat 2 the servants (仆人). After the meal Martin stood up and said to the servants."Now, my good friends, I 3 for you." He sang several songs and the servants 4 quite pleased. Then the rich woman asked 5 to come to the sitting-room." We are waiting for your songs. 6 you ready?" the woman asked. "I am 7 ," Martin said. "I have sung already. I usually sing 8 in one evening, and I can't sing 9 ." And with a polite (礼貌) " 10 ", he left the rich woman's house. |
| ( )1. A. doesn't invite ( )2. A. with ( )3. A. sang ( )4. A. was ( )5. A. the servant ( )6. A. Were ( )7. A. sad ( )8. A. one ( )9. A. two ( )10. A. Good night | B. don't invite B. for B. shall sing B. were B. the friend B. Is B. sorry B. once B. once B. Good afternoon | C. didn't invite C. at C. sing C. are C. the singer C. Are C. glad C. twice C. twice C. Good day |