热扣合法用于修复（）零件的裂纹.
A.重要
B.大而重
C.精密
D.难拆和难运输
参考答案：B
39. Thank you for your help. ______ for your help, I wouldn’t have succeeded in my experiment.
A．If it is not
B．Were it not
C．Had it not been
D．If they were not
人类文化大系统不包括（）
A、物质文化
B、制度文化
C、精神文化
D、饮食文化
