Thirty years ago this month，China's leaders launched an economic revolution.___________the door to free market reforms and foreign trade．
| A．to open | B．opened | C．opening | D．having opened |
The boy will make a lot of trouble when __________ alone.
| A．leaving | B．leave | C．left | D．being left |
Allow children the space to voice their opinions, ____they are different from your own.
| A．until | B．even if | C．unless | D．as though |
Peter has been out of work for half a year, so he wants to ______a job in this company.
| A．prepare for | B．apply for | C．wait for | D．care for |
．—I’m sorry to have brought you so much trouble.
— _________.
| A．My pleasure | B．No problem |
| C．That’s right | D．You’re welcome |
—I never thought Jerry can speak English so fluentlyl.
—Well, actually he_________in the USA for two years.
| A．was staying | B．stays | C．stayed | D．has stayed |