下列哪种植物可以作为监测空气污染程度的指示植物()
A:种子植物
B:蕨类植物
C:苔藓植物
D:藻类植物
It suddenly occurred to him ____ he had left his keys in the office.
判断下列图片与单词是否相符,用“正确”或“错误”表示。
shirt
( )