Our country （ ） a lot so far. Yes. I hope it will be even （ ）.
（A）has changed; well
（B）changed; good
（C）has changed; better
（D）changed; better
The conference （ ） a full week by the time it ends.
（A）must have lasted
（B）will have lasted
（C）would last
（D）has lasted
A First - aids worker risked his life saving two tourists who （ ） in the mountains for two days.
（A）are trapping
（B）have been trapped
（C）were trapping
（D）had been trapped
