选择一合适的短语将A和B两部分组合成六个既完整又符合逻辑的句

1)The training center was established because of(due to)low level of supervisory knowledge

2)The failure of the report was due to imprecise terms of reference

3)The training course was canceled，owing to low staff attendance.

4)Output went down because of(due to)difficuh trading conditions

5)Conditions everywhere have been seriously worsened，owing to the postwar rise in prices.

6)The increased efficiency was due to the improved training methods.

7)the crops completely failed，owing to a disease that had set in.