人体肺循环的起点、终点分别是( )
A:左心房
B:左心房和左心室
C:右心室和左心房
D:右心房和右心室
选择单词,补全短文
hot China winter people old east
Shanghai is the biggest city in ____.It's in the ____ of China. It's got a lot of ____.It's an ____ city. It's very ____ in summer and it's cold in ____.
NA代表阿伏加德罗常数,下列有关叙述正确的是
某同学利用如图所示电路,测量额定电压为2.5V小灯泡的额定功率,下列说法错误的是( )
为确保生命安全,下列处理事故的方法正确的是( )