单项选择题 下列叙述中属于造成目前世界粮食问题的原因是（ ）

单项选择题 The art of war has undergone such changes that _______．A.we no longer use any French words of the Middle AgesB.many words once common are not used any longer and they are replaced by Italian wordsC.French military terms have disappeared from the English languageD.many words once common are now only in historical use and their places have been taken by the newly-borrowed words

多项选择题 关于多发性骨髓瘤的描述下列哪些是正确的（）