______ 2010 Shanghai World Expo is a perfect opportunity to get ______ panoramic (全景的) view of the whole world without traveling thousands of miles.
I was only when I reread this poems recently _____ I began to appreciate their beauty.
.______is a fact that English is being accepted as an international language.
It was not until 1920 ______ regular radio broadcasts began.
I was disappointed with the film . I had expected ______ to be much better.
It was not _____ she took off her glasses _____ I realized she was a famous film star.