There ______ a large number of students in our school. The number of the students _______ over three thousand.
A:is; is
B:are; are
C:is; are
D:are; is
某矿泉水标签上印有主要成分有:K(1.0~27.0)mg/L;Cl(1.0~24.0)mg/L;Mg(0.1~5.0 )mg/L。这里的K、Cl、Mg是指 ()
如图为某植物叶肉细胞中的两种膜结构以及发生的化学反应,下列有关叙述错误的是( )