—What's the matter with John? He has been sitting there for hours.
—A postcard from his father ________ an attack of homesickness in him.
| A．took up | B．set off |
| C．brought in | D．built up |
-- 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 |
She’ll never forget her stay there ________ she found her son who had gone missing two years before.
| A．that | B．which | C．where | D．when |