【单选题】He raised his eyebrows and stuck his head forward and ______ it in a single nod, a gesture boy, used then for O. K. when they were pleased.
【单选题】He () his eyebrows proudly.
【简答题】He raised his eyebrows and stuck his head forward and ________ it in a single nod, a gesture boys used then for O.K. when they were pleased. A) shrugged B) tugged C) jerked D) twisted
【简答题】震惊全国的“三鹿奶粉”事件中的罪魁祸首是三聚氰胺(分子结构如图).三聚氰胺是一种重要的化工原料,由于其含氮量高,且目前国际上又通用“测氮法”标定牛奶中蛋白质含量,于是一些不法商人就将其混入奶粉中以“提高”奶粉的品质. (1)三聚氰胺的分子组成为 _____ ; (2)三聚氰胺中碳、氢元素的质量比为 ____ ; (3)三聚氰胺中氮元素的质量分数为 _ (计算结果精确到 0.1%); (4)奶粉中蛋...
【简答题】拉伸实验中 , 试样所受的力为 ( ) A 、冲击 B 、多次冲击 C 、交变载荷 D 、静态力