It is impossible for humans to live on the moon_______ there is no water_______ air there.
-What do you think of the young woman singer? -It's hard to say, but her voice __________ beautiful.
To his surprise, Jack got a low __________ in the final exam.
He practices __________ English every day.
I __________ my pen everywhere, but I didn't find it.
-The light in the office is still on. -Oh, I forgot __________.