1.It is a pity that you give up in the middle.2.Since you have agreed on it,there is no need to ask the lawyer for help.3.The more Einstein learned,the more questions he found he had to think.4.No matter how hard it is,we will try to do it well.5.That no one told him about the meeting accounted for his absence yesterday.6.People usually think that that more you use your brain,the more actively you brain works.