If you keep your attention _______ learning, then you can get good grades in your subjects.
The Thinker, head in hand, resting his right arm on his left knee, gained its current title when ______ in Paris in 1890.
Poor as she was, she was eager for attention. Thus she had to think of borrowing some jewels to ______ at the party.
A ______ identification card is required when you purchase foreign money from the Bank of China.
It ______ me all of a sudden that I had left my key to the car in the office.
______ there are living creatures in the outer space as those on Earth hasn’t been proved so far.