---He's already back to Australia,__________?---____________. He is on a visit to Shanghai.A.isn't he; NoB.hasn't he; YesC.isn't he; YesD.hasn't he; No 答案:A解析:本题考查的是反义疑问句,因为陈述句为肯定句,后面简略问句为否定句,,回答的时候根据实际情况回答,事实上是肯定的,用yes,事实上是否定的用no,根据后面的He is on a visit to Shanghai.故选A按F2、Cl2、Br2、I2的顺序,下列变化规律不正确的是 ①单质颜色逐渐加深 ②密度逐渐增大 ③熔点与沸点逐渐升高 ④X2的氧化性增强⑤HX稳定性减弱 ⑥X-还原性减弱 ⑦与H2反应逐渐困难 ⑧与水反应逐渐困难A.①③ B.②⑤C.④⑥ D.⑦⑧