A:清澈、富含有机质的江河中
B:浑浊、急流、富含有机质的江河中
C:潮湿、疏松、富含有机物的土壤中
D:干燥、疏松的河沙中
注意:1. 词数不少于 60. 2. 短文的开头已给出,不计入总词数。
There was a problem with the parking place for bikes in our school.