植物细胞特有的能量转换器是( )
A:线粒体
B:叶绿体
C:细胞壁
D:液泡
已知圆C和y轴相切,圆心在直线x﹣3y=0上,且被直线y=x截得的弦长为27,求圆C的方程.
Studying in groups is necessary __________ you want to do well in school.
Lucy was born ______ January 30th, 1998, when her sister got married ______ a fashion designer.