they are talking to each other!—Yes. They are really happy to see each other.

What’s this in English? —It’s ____ eraser.

Those_____ have caught H1N1 disease must be kept off from us.

Seeing the car trapped in the snow drift, the driver didn’t know ______ it.

Only after he had spent several nights working on the math problem_______to wonder whether the problem was wrongly set．