听下面一段材料，回答第1-4题。 1. What is the main purpose of the speech? A. To tell the students how to collect rubbish. B. To compare different recycling programs. C. To encourage the student to join in a recycling program. 2. According to the program, where should plastic bags be put? A. Into white cans. B. Into blue cans. C. Into pink cans. 3. According to the speaker, why are many recycling programs NOT successful? A. Because most recycling rules are not clear. B. Because most collecting tasks are too difficult. C. Because most people are unwilling to sort rubbish. 4. What is the job for the volunteers? A. To sort the collected rubbish and then deliver it. B. To collect the sorted rubbish and then deliver it. C. To collect the sorted rubbish and then recycle it.