At the Copenhagen conference, all the countries were called on to do all they could to control greenhouse gas emissions it was too late.
| A．when | B．after | C．until | D．before |
He is a man of ____ and he had a lot of interesting ____ in his life.
| A．much experience, experiences | B．many experiences, experience |
| C．much experience, experience | D．many experiences, experiences |
I don’t think _____ possible to master a foreign language without much memory work and practice.
| A．this | B．that | C．it | D．/ |
Work hard at your lessons, ______ you’ll fail the exams again.
| A．and | B．but | C．or | D．which |
He devoted all the time _____ his research .
| A．to do | B．doing | C．to doing | D．did |
Mr. Liu dreamed ____ a big house for his parents after they retire.
| A．to buy | B．to buying | C．of buying | D．of being buying |