A:甲、乙
B:甲、丙
C:丙、丁
D:乙、丁
Don't be ____ (暴露于) to the strong sunlight, which may damage your skin.
项目
杂草密度
(株/m2)
物种丰富度(种)
杂草相对优势度
草龙
节节菜
稗草
陌上菜
异形莎草
常规区
40
12.0
0.247
0.189
0.100
0.102
0.094
稻鸭区
2.3
5.3
0
0.259
0.271
0.089
- Tom, you look tired this morning. What's wrong?
- I was busy and I didn't go to bed _________ 12 o'clock last night
下图是有关中国古代农业生产方式示意图,推断空缺方框中最可能填写的是( )