A:细胞
B:组织
C:器官
D:植物体
解决问题。
John: What do you do on Sundays?
Tom: I read books and watch TV. What do you do on Sundays?
John: I do my homework . What about you, Mary?
Mary: I clean my room and watch TV.
John: You're helpful.
小明想知道小灯泡的亮暗程度与什么因素有关.找来额定电流小于0.6A,额定电压是2.5V的灯L1,接在电源电压恒为6V的电路中,按照如图甲所示电路探究.