题目

Ms. Jones was afraid that the old man couldn't hear what she said, so she raised her ______. A . neck B . voice C . hand D . knee 答案：B为了估计鱼塘里有多少条鱼，我们从中捕捞出100条，做上标记后放回鱼塘里，经过一段时间后再从中捞出300只，若发现有标记的鱼有15条，则可估计该鱼塘中有 条鱼．