A:might
B:would
C:could
D:should
-- Where is dad, mum?
-- He is ____his report in the room. He needs it for a meeting.
由3个亿, 5个百万, 2个千和8个十组成的数写作:____,读作:____。
人的口腔上皮细胞中的能量转换器是( )
读我国部分区域图,判断下列各题.