10．请根据所听内容，在每小题给出的三个选项中，选出一个能完成句子的最佳答案，并将答题卡上对应题目所选的选项涂黑．录音听两遍．
16．Ais the hardest part in the recycling program．
A．Searching B．Collecting C．Carrying
17．There will beBkinds of dustbins in the school next week．
A．one B．three C．four
18．Each volunteer will work forBa week．
A．only two hours B．less than five hours C．more than five hours
19．The waste clothes should be put in theBdustbin．
A．black B．red C．blue
20．The speaker is speaking toC．
A．some teachers B．some cleaners C．some greener volunteers．
