英語：情態(tài)動詞、反意疑問句?（選擇題）
①This is a green jeep,＿?
A.isitB.isn'titC.isthisD.isn'tthis
②Tom's never late for class,＿?
A.is heB.isn't heC.has heD.hasn'the
③Nothing is difficult if you put your heart into it,＿?
A.is itB.isn't itC.are theyD.don't you
④You'd better not smoke,＿?
A.did youB.didn't youC.had youD.hadn't you
請幫忙想一下.謝謝.
請說明為什么。謝謝。