— Yeah. They ______ here from Hainan yesterday.

My new ___________.（    ）

①求电源电压U．

②将滑动变阻器滑片P移到某处，发现电流表A的示数已达到某量程的满刻度，且各元件都能正常工作，求此时滑动变阻器连入电路的阻值．

③现用R₀替换R₁且能使电路中的电流达到最大，电路各元件都能正常工作，求替换的R₀的最大阻值．

从方框中选词并用其适当形式填空 

Many____like playing computer games after school. 
Rui Chenggang is a ____ from CCTV. 
Mrs Green likes writing ____for children.
As a____ ,  he works late at night.
During big festivals,  the ____ are very busy.