He ______busy yesterday,or he______you with your experiment.
| A．was;had helped |
| B．was;would have helped |
| C．had been;would have helped |
| D．were;would have helped |
I don't think the experiment is ________ failure.At least we have gained ________ experience for future.
| A．/；the | B．a；the | C．a；/ | D．/；/ |
Being able to afford ________ drink would be ________ comfort in those tough times.(2012·山东)
| A．the；the | B．a；a | C．a；/ | D．/；a |
First impressions are the most lasting.After all, you never get ________ second chance to make ________ first impression.(2010·北京)
| A．a；the | B．the；the | C．a；a | D．the；a |
It is generally accepted that ________ boy must learn to stand up and fight like ________ man.(2011·全国)
| A．a；a | B．a；the | C．the；the | D．a；/ |
We can never expect ________ bluer sky unless we create ________ less polluted world.(2009·安徽)
| A．a；a | B．a；the | C．the；a | D．the；the |