一个等腰三角形中两个角的度数比是4:1,这个等腰三角形的顶角是____或____。
为验证质量守恒定律,某同学设计了如图实验. 该实验能否达到实验目的?请说明理由.
有关农业生产对环境影响的叙述,正确的是 ( )
Please look _______ the pictures on the wall.
Bob has got good exam results. His parents are proud of his ______.