________ global energy safety, all the countries have been called on to take joint efforts ．
| A．Having ensured | B．Ensuring |
| C．To ensure | D．To have ensured |
— Have you finished all your homework?
— Of course. I ________ it before I went out to play football.
| A．had finished | B．have finished |
| C．finished | D．was finishing |
—He failed in the exam again.
—He __________his teacher’s advice.
| A．should not have followed |
| B．should not follow |
| C．mustn’t follow |
| D．should have followed |
When first to the market, these products enjoy great success.
| A．introducing | B．introduced |
| C．introduce | D．being introduced |
Armed with the information you have gathered, you can ___ preparing your business plan.
| A．set out | B．set about |
| C．set off | D．set up |
Cleaning women in big cities usually get by the hour.
| A．pay | B．paying | C．paid | D．to pay |