Ⅰ ( )1. Nice to meet you. ( )2. Where does your brother work? ( )3. What can I do for you? ( )4. Would you like something to drink? ( )5. How much are the pants?
Ⅱ A. They’re 30 yuan. B. I want a skirt for my daughter. C. Some milk, please. D. Nice to meet you, too. E. He works in a hospital.
C2H4（g） 
C2H4（g）+2H2（g）
CH4（g） △H= -Q1 kJ/mol 
C2H2（g） △H= -Q2 kJ/mol 
C2H4（g） △H= -Q3 kJ/mol