shell still meaning in English

简单的蒸馏釜

Which of the shooting grounds mentioned in the answer to above have not yet been cleared , and whether an estimate has been made of the number of dud shells left behind in those shooting grounds , and whether these dud shells still pose a danger at present ; and
有哪些在a项答覆所述的操炮区仍然未被清理有否估计在该些操炮区内遗留下多少没有爆炸的弹头，及该些弹头现