根据题意得：a+1≠0，解得：a≠-1，故答案为a≠-1．
Many people agree that ______ knowledge of English is a must in _______ international trade today.
A．the, an
B．a, 不填
C．the, the
D．不填, the
慢性肾功能不全出现肾性贫血最合适的治疗药物是
A．口服碳酸钙
B．必需氨基酸疗法
C．补充1，25-(OH)2D3
D．促红细胞生成素
E．血液透析治疗
