听力原文： Hello, Dave, it's Sam calling from the logistics warehouse. Sorry to be an inconvenience to you, but when I left the head office this morning, I forgot a bag of samples that I was supposed to pass on to the material buyers. I was informed that you would be visiting the warehouse this afternoon, and if it's not too much trouble, I was wondering if you could bring the samples I left in your room with you when you come. On another note, there are a couple of purchase authorizations I'd like you to look over. They seem a little bit out of the ordinary, and I was wondering if you could keep me up to speed on the latest purchasing arrangements. I suspect there has been a couple of irregular purchases that may cause us to have an overabundance of stock in our inventory that we may have to have a clearance sale later this year, and I'd like to reduce this risk as much as possible if I can. What is the main purpose of the call?