—All of them ________ the museum.
A:where are the students; have gone to
B:where are the students; have been to
C:where the students are; have gone to
D:where the students are; have been to
下图是人们为_____事件祈愿的漫画之一,表达了人们的默默祝福! ( )
Cs是稳定的核电荷数最大的碱金属元素,下列关于铯及其化合物的叙述,正确的是( )