are in my grandparents' room.
A:A key
B:The keys
C:The key
D:Key
There are 30 classrooms ____________ our school. Mine is _____________ the second floor.
绿色植物以____和水为原料,通过____作用制造的有机物,不仅用以满足植物本身的生长需要,同时还是动物和人所需____的最终来源.
读青藏地区图,回答下列问题.