莫瓦桑从石墨中烧出了金刚石。()
参考答案:错
从生态学上考虑,农民在农田里除草是为了调整 [ ]
A.作物和杂草间的生态平衡
B.生态系统的物质循环
C.水和肥料的使用效率
D.生态系统的能量流动方向
My cousin worked all winter vocation, saving money to______ his hobby of collecting stamps.
A.search
B.hunt
C.seek
D.pursue