weapon/weaponry
【问】 The crossbow is a medieval 
such a way as 
it greater strength
an ordinary bow.(TOEFL，82. 11)
答案规定A(weaponry)为错误。难道weaponry不是一个单数名词吗?为什么不能用不定冠词?
【答】 英语里有一些名词是表示一类事物的总称的，例如：personnel(人员)，poetry(诗)，ma-chinery，scenery，jewelry。这些名词不能加-s表示复数，也不能与不定冠词连用。weaponry也属于这类名词。这类名词都有其相对应的表个体的名词：weapon，person，poem，machine，scene，jewel。
请做下面的试题：
We have____.
A. a piece of jewelry B.a bar of jewelry
C. a little bit of jewelry D. a jewelry
赵振才 编著.英语常见问题解答大词典.哈尔滨：黑龙江人民出版社.1998.第1272页.
- not... because
- not... but
- not... but
- not...but
- not... but...is/are
- not...but(关系代词)
- not certainly/certainly not
- note
- no teacher
- not even
- not even
- not every
- not half
- nothing
- nothing but
- nothing but /anything but
- nothing but do/to do
- nothing but do/to do
- nothing but+Ns is/are
- nothing but watch
- nothing if not
- nothing if not
- nothing less than
- nothing like
- nothing more than