When Americans send an invitation they often send it ______ .
A. 3 or 4 days in advance
B. a week in advance
C. 1 day in advance
D. more than 10 days in advance
The writer broke ______ in the end.
A. three doors
B. three glasses
C. three windows
维生素B12缺乏，有神经系统表现，维持治疗的时间为
A．chose itB．hanged itC．picked it up
A. chose it
B. hanged it
C. picked it up
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