题目

How do students around the world get to school? Do you know? We ___1___ a survey about it last month and this is what we ___2___． In North America，most students go to school ___3___ the school bus．Some students ___4___ walk or ride bikes to school．In ___5___ parts of the world，things are different．In Japan，most students take trains to school，___6___ others walk or ride their bikes，too．In China，it deepens on ___7___ you are．In big cities，students usually ride bikes to school or take buses，but in small villages，students go to school ___8___ and it usually ___9___ th3、如图所示，闭合电键S后，小磁针的N极由图示静止位置向左偏转，则下列判断中正确的是（　　）A、通电螺线管左端是S极，电源a端是正极B、通电螺线管左端是S极，电源b端是正极C、通电螺线管左端是N极，电源a端是正极D、通电螺线管左端是N极，电源b端是正极