[单选题][难度:0.5][分数:1]程序编制中首件试切的作用是( )。
A.检验零件图样的正确性
B.检验零件工艺方案的正确性
C.检验程序单的正确性,并检查是否满足加工精度要求
D.检验数控程序的逻辑性

The funny thing about how a bank works is that it functions because of our trust. We give a bank our money to keep it safe for us, and then the bank turns around and gives it to someone else in order to make money for itself. Banks can legally extend considerably more credit than they have cash. Still, most of us have total trust in the bank’s ability to protect our money and give it to us when we ask for it.
Why do we feel better about having our money in a bank than we do having it under a mattress(床垫) Is it just the fact that they pay interest on some of our accounts.’ Is it because we know that if we have the cash in our pockets we’ll spend it Or, is it simply the convenience of being able to write checks and use debit cards(借记卡) rather than carrying cash Any and all of these may be the answer, particularly with the conveniences of electronic banking today. Now, we don’t even have to manually write that check -- we can just swipe(刷卡) a