_________ in drinking water have spread the illness.
（A）Barriers
（B）Bacteria
（C）Barn
（D）Bark
参考答案
继续答题：下一题
更多雅思试题
- 1I’m worried about the appearance of the floor.I need to _____ it.
- 2The merchant decided to use ______ to carry his goods across the desert.
- 3The hunter watched for the _______ to come out of the burrow.
- 4This is the military ______.Nobody is allowed to get in without permission.
- 5I am afraid it was a _____ for you to do this.
- 6A general _______ is held in the United States every four years.
