with和by在意思为"用"时区别是什么？
在2016年高考全国卷-丙英语试题语法填空题目中，最后一个空为  
Chopsticks are not used everywhere in Asia. In India , for example , most
people traditionally eat ______ their hands.  
答案是with，不明白为什么不能用by，某度了一下，大多数解释的区别是如果是实物（如手，锤子）用with，非实物（如手段，道理）用by，但新东方一本高中英语词汇的参考书上by这个词的解释里有例句:
I would like to pay by cheque.可支票不是实物吗？请问这两个词到底如何使用。
教大家一个简单的办法，with 其实是with the presence(involvement) of 的缩写。by其实是by means of的缩写。用手吃饭,eat with the presence (involvement) of your hands. 但如果说eat by meansof your hands无论如何都说不通。用心思考，think with the involvement of your brain ，但说thinkby means of your brain 也说不通。用支票支付，pay by means of cheque ，说成pay with thepresence( involvement ) of cheque 也说不通。开车上班，go to work by means of car，说成go towork with the presence (involvement) of your car说不通。同理，用邮件联系，contact by meansof email用电加热，heat by means of electricity用紫外线消毒，disinfection by means ofUV用笔写字，write with the presence (involvement) of a pen。用爱发电，generate power withthe presence (involvement) of love。