题目

Learning a second language fuels children’s intelligence and makes their job prospects brighter.    36    the fact is, in U.S.A, as in many other English speaking countries, speakers of two or more languages are in the    37   . Eighty-four per cent of US people are monolingual (speakers of only one language). This leaves a small number who    38    to speak two or more languages. No matter how proud people are of their cultural roots, to speak anything          ___39    English is a marker of difference here. That’s why fourteen-year-old Umar is   如图所示是红星中学九年级物 理课外实践活动小组设计的风力测量仪的电路示意图，其电源电压U=3V，电路保护电阻R1= 2Ω，均匀电阻丝的阻值为R2= 3Ω.金属丝（电阻忽略不计）的上端固定在O点．下端系有一块塑料片A，当风从右向左吹动塑料片时，金属丝向左摆动并与电阻丝保持 良好的接触．风力表由电压表改装而成 （1）无风时，塑料片竖直下垂，电压表示数是多少？电路中的电流是多少？（2）风力最强时，金属丝滑至电阻丝的最左端，电压表的示数是多少？（3）为什么不在电路中串联电流表，把电流表改装成风力表？