When it______air pollution, Beijing faces the three “C” s-----cars,coal and construction,which lead to Beijing's thick air pollution.
_____ with fear, the boy stood still to avoid _______.
Tom always feels it necessary that he ________English.
On our arrival, we found Tom _____at the desk and ______a letter.
The boy is often found _____in reading books.
Though _______ money, his parents managed to send him to university.