当血液流经鲫鱼的鳃之后,血液中显著增加的成份是( )
A:养料
B:废物
C:氧气
D:二氧化碳
如图示是某同学连接的电铃电路,开关闭合后,电路中始终有电流,但电铃只响一声就不再响了,原因是
—It's ____ the station.
Spend more time talking with your parents, _______they may not well understand you.