矿石中有用成份的质量与矿石的质量的百分比叫（）。
参考答案：矿石品位
_____ the advantages against the disadvantages, I decided to take up the job as a clerk in the bank. [ ]
A. To weigh
B. Weighing
C. Weighed
D. Having weighed
光纤通信系统中何谓带宽限制系统？
