It is time the government ______ the law into effect.
A. is putting
B. put
C. puts
D. will put
制备易氧化药物注射剂应加人的金属离子螯合剂是
A. 碳酸氢钠
B. 氯化钠
C. 焦亚硫酸钠
D. 枸橼酸钠
E. 依地酸钠
His mother is going to stay in Beijing for ______.
A. some times
B. some time
C. sometime
D. sometimes
Ann was not careful enough; ______ she wouldn't have made such a silly mistake.
A. nevertheless
B. however
C. otherwise
D. although
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