A:2SO2(g)+O2(g)2SO3(g)△H<0
B:4NH3(g)+5O2(g)4NO(g)+6H2O(g) △H<0
C:H2(g)+I2(g)2HI(g)△H>0
D:C(s)+H2O(g)CO(g)+H2(g)△H>0
“上天入海”是香港地区解决人多地少的有效措施,具体是指( )。
①大力发展航海业 ②大力发展航空业 ③填海造陆 ④建筑高楼
下列三个现象:①灯头里的两个线头相碰;②插座中的两线头相碰;③照明电路的开关里两线头相碰.
其中可能引起保险丝熔断的是( )
下列说法不正确的是( )
①____ What's your friend's name? A.Yes, she is.
②____ Does she have long hair? B.Yes, they are.
③____ Are they good friends? C.He's short.
④____ Is your brother tall or short? D.Yes, she does.
⑤____ Is she thin? E.Liu Tong.