A:①②③
B:②③④
C:①②④
D:①③④
选词填空。
欢乐 欢庆
①全校师生一起____“六一”儿童节。
②今天,同学们在庆祝会上____地歌唱。
6C(s)+5H2(g)+3N2(g)+9O2(g)═2C3H5(ONO2)3(l)△H1
2H2(g)+O2(g)═2H2O(g)△H2
C(s)+O2(g)═CO2(g)△H3
则反应4C3H5(ONO2)3(l)═12CO2(g)+10H2O(g)+O2(g)+6N2(g)的△H为( )
When do you ________ every day?
What are people supposed to do when they meet for the first time in China?( )