________ to playing games recently，he is easy to feel sleepy in class.
| A．Addicted | B．Addicting | C．Having addicted | D．To addict |
Just as Professor Scotti often______ it, success is ninety-nine percent mental attitude.
| A．gets | B．makes |
| C．puts | D．means |
-- Do you think it's a good idea to make friends with your students?
-- _____ , I do. I think it's a great idea.
| A．Really | B．Obviously |
| C．Actually | D．Generally |
Daniel's family____their holiday in Huangshan this time next week.
| A．are enjoying | B．are to enjoy |
| C．will enjoy | D．will be enjoying |
– I wonder how much you charge for your services.
-- The first two are free ____ the third costs $30.
| A．while | B．until |
| C．when | D．before |
We can never expect____ bluer sky unless we create_____less polluted world.
| A．a; a | B．a; the |
| C．the; a | D．the; the |