My dad is forty years old. He is short. He has big eyes Beause he didn’t study hard when he was a child. Now he has to ......

对目前常用的《机械原理》教科书中的“极位夹角”定义提出异议，并从广义上对“极位夹角”作了进一步的定义．......

ＴｈｅＤＩＮＫＰｈｅｎｏｍｅｎｏｎｉｎＣｈｉｎａ──ＴｈｅｉｎｆｌｕｅｎｃｅｏｆｈｉｇｈｅｒｉｎｃｏｍｅｓａｎｄｈｕｒｒｉｅｄｌｉｆｅｓｔｙｌｅｓｃｏｎｔｉｎｕｅｓｔｏｔｈｒｅａｔｅｎｔｒａｄｉｔｉｏｎａｌＣｈｉｎｅｓｅ　ｖａｌｕｓｅ．．Ｂｙｓｔａｆ.........