以NA代表阿伏加德罗常数,则关于热化学方程式C2H2(g)+O2=2CO2(g)+H2O(l);△H=-1300kJ/mol的说法中,正确的是
It is often ______ that human beings are naturally equipped to speak.
I can’t leave. She told me that I ______ stay here until she comes back.
—— Do you mind my opening the window? It’s a bit hot in here. —— ______ , as a matter of fact
It’s high time you had your hair cut ; it’s getting _______ .
My friend showed me round the town, ______ was very kind of him.