r开头b结尾的单词

　　Appearance and Physical Property of Rhubarb Water Extract by Different Drying Methods

　　不同干燥条件大黄水提物的外观及理化性质比较研究

　　Objective: To study the effect of rhubarb on gastrointestinal dynamics.

　　目的：研究大黄对胃肠动力学的影响。

　　I rubbed at the stain on the cloth.

　　我擦了擦布上的污渍。

　　It sounded like two pieces of wood rubbing together.

　　听起来就像是两块木头在一起摩擦。