夜间卧室内不宜放置过多的花草,过多会影响人的健康,其原因是( )
A:使室内空气潮湿
B:与人争夺氧气
C:与人争夺二氧化碳
D:释放过多的氧气
(T=Teacher S=Student)
T: Hello!
S: ____
T: I am your new teacher.____
S: My name is Tom.
T: ____
S: Very well, thank you.
T: Nice to meet you.
A. How are you?
B. Hi!
C. What's your name?
D. Nice to meet you, too.
如图甲所示,当开关S从点2转到1时,电流表和电压表对应的示数如图乙所示,由图甲和图乙中的信息可知,电源电压是____ V,电阻R2的阻值是____ Ω,电阻R2的I-U图像是丙图中的____ .(选填“a”或“b”)
下表是元素周期表的一部分,针对所给的10种元素,完成下列各小题.
ⅠA
ⅡA
ⅢA
ⅣA
ⅤA
ⅥA
ⅤⅡA
0
2
C
N
O
3
Na
Mg
Si
S
Cl
Ar
4
Ca