A:a; an
B:不填; an
C:不填; the
D:a; the
The robber hit and _______ Mr. Zhang and took away his wallet.
①2CH4(g)+4O2(g)═2CO2(g)+4H2O(l)△H=﹣890.3kJ•mol﹣1
②2H2(g)+O2(g)═2H2O(l)△H=﹣571.6kJ•mol﹣1
③C(s)+O2(g)═CO2(g)△H=﹣393.5Kj•mol﹣1
下列选项中,可以看作是一个生态系统的是( )
实施科教兴国战略,关键是( )。
____