—If I work hard at my lessons from now on, can I do well in them?

—Sure. ___________.

A．All rivers run into sea

B．Every day is not Sunday

C．Better late than never

D．Practice makes perfect

按下起动按钮时，保位和吸拉线圈（），通过电流产生（）力，吸引铁芯移动。

A.串联，较小

B.串联，较大

C.串联，较小

D.并联，较大