Kitty works _______ at the lessons.[ ]
A. hardly
B. well
C. hard
D. good
答案：C
---Look! Dad, my College Graduation Certificate! I’ve got it!
---____dear! You have finally realized your dream.
A．congratulation
B．celebrations
C．congratulations
D．greetings
如何保证SCR系统NOx脱除效率？
